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CBSE - Class 9 Mathematics Polynomials Worksheet
EXERCISE 2.2
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Solution:
We are given a single-variable polynomial function of degree 3 (a cubic polynomial). The polynomial is defined as:
$p(x) = x^3$
Our objective is to evaluate this polynomial at three specific discrete points in its domain: $x = 0$, $x = 1$, and $x = 2$. [Per the Substitution Principle of Functions, evaluating a polynomial $p(x)$ at a specific value $x = a$ requires replacing every instance of the variable $x$ in the expression with the constant $a$].
To find $p(0)$, we substitute $x = 0$ into the polynomial equation.
[Theoretical Justification: The zero product property and the definition of exponentiation state that zero raised to any positive real power is strictly zero. Geometrically, this indicates that the graph of the polynomial passes exactly through the origin $(0,0)$].
To find $p(1)$, we substitute $x = 1$ into the polynomial equation.
[Theoretical Justification: The number 1 is the multiplicative identity. Any real number multiplied by 1 remains unchanged, hence 1 raised to any real power is always 1].
To find $p(2)$, we substitute $x = 2$ into the polynomial equation.
[Theoretical Justification: Exponentiation represents repeated multiplication. The rapid growth from $p(1)=1$ to $p(2)=8$ demonstrates the non-linear, cubic expansion characteristic of degree-3 polynomials].
Below is the precise Cartesian mapping of the polynomial $p(x) = x^3$. The specific points we evaluated—$(0,0)$, $(1,1)$, and $(2,8)$—are plotted to visually confirm the cubic curve's trajectory.
| Input Variable ($x$) | Substitution ($x^3$) | Output Value ($p(x)$) |
|---|---|---|
| $0$ | $0^3$ | $0$ |
| $1$ | $1^3$ | $1$ |
| $2$ | $2^3$ | $8$ |
Final Solution: For the polynomial $p(x) = x^3$, the evaluated values are $p(0) = 0$, $p(1) = 1$, and $p(2) = 8$.
Solution:
We are given the linear polynomial:
$p(x) = lx + m$
We need to verify whether the given value of $x$ is a zero (or root) of the polynomial:
$x = -\frac{m}{l}$
[By the Fundamental Theorem of Algebra and the definition of polynomial roots, a real number $a$ is considered a "zero" of a polynomial $p(x)$ if and only if evaluating the polynomial at $x = a$ yields exactly zero, i.e., $p(a) = 0$. Furthermore, for $p(x)$ to be a valid linear polynomial of degree 1, the leading coefficient $l$ must not be equal to zero ($l \neq 0$).]
To test the condition $p(a) = 0$, we substitute $x = -\frac{m}{l}$ into the polynomial expression $p(x)$.
$p\left(-\frac{m}{l}\right) = l\left(-\frac{m}{l}\right) + m$
Next, we perform the multiplication. Since $l$ is in the numerator of the coefficient and the denominator of the substituted fraction, they cancel each other out [Per the multiplicative inverse property, assuming $l \neq 0$]:
$p\left(-\frac{m}{l}\right) = \left(l \cdot \frac{-m}{l}\right) + m$
$p\left(-\frac{m}{l}\right) = -m + m$
Combining the terms yields:
$p\left(-\frac{m}{l}\right) = 0$
Because the polynomial evaluates to zero at this specific value of $x$, the condition for it being a zero of the polynomial is perfectly satisfied.
Geometrically, the zero of a polynomial corresponds to the $x$-intercept of its graph. For the linear function $y = lx + m$, the line crosses the $x$-axis exactly at the coordinate $\left(-\frac{m}{l}, 0\right)$. The SVG below illustrates this relationship (assuming $l > 0$ and $m > 0$ for visual representation).
Final Solution: Yes, $x = -\frac{m}{l}$ is a zero of the polynomial $p(x) = lx + m$, because substituting this value into the polynomial yields exactly $0$.
Solution:
We are given the following cubic polynomial in terms of the variable $t$:
$p(t) = 2 + t + 2t^2 - t^3$
To find the values of $p(0)$, $p(1)$, and $p(2)$, we must apply the Polynomial Evaluation Principle. This principle states that the value of a polynomial $p(t)$ at a specific real number $t = a$ is obtained by substituting $a$ for every instance of $t$ in the polynomial expression [Per the fundamental definition of a polynomial function].
We substitute $t = 0$ into the polynomial equation. This operation isolates the constant term, as all terms containing the variable $t$ will evaluate to zero.
Geometrically, this represents the $y$-intercept of the polynomial graph at the coordinate $(0, 2)$.
Next, we substitute $t = 1$ into the polynomial. Evaluating a polynomial at $t = 1$ effectively yields the sum of its coefficients and the constant term.
This corresponds to the coordinate point $(1, 4)$ on the Cartesian plane.
Finally, we substitute $t = 2$ into the polynomial. We must carefully follow the order of operations (PEMDAS/BODMAS), evaluating the exponents before multiplying by the coefficients.
This corresponds to the coordinate point $(2, 4)$ on the Cartesian plane.
Below is the precise Cartesian plot of the polynomial $p(t) = -t^3 + 2t^2 + t + 2$. The specific points we evaluated—$p(0)$, $p(1)$, and $p(2)$—are explicitly marked to demonstrate their spatial relationship on the curve.
| Variable Input ($t$) | Polynomial Output ($p(t)$) |
|---|---|
| $t = 0$ | $2$ |
| $t = 1$ | $4$ |
| $t = 2$ | $4$ |
Final Solution: The evaluated values for the polynomial are $p(0) = 2$, $p(1) = 4$, and $p(2) = 4$.
Solution:
We are given the linear polynomial:
$p(x) = 2x + 5$
In algebra, the zero of a polynomial is defined as the specific value of the variable (in this case, $x$) that makes the value of the entire polynomial equal to zero. Geometrically, this corresponds to the x-coordinate of the point where the graph of the polynomial intersects the x-axis (the x-intercept).
To find the zero of the polynomial, we must equate the polynomial function $p(x)$ to $0$. [Per the Fundamental Theorem of Algebra, a polynomial of degree 1 will have exactly one real zero].
$p(x) = 0$
Substituting the given expression for $p(x)$:
$2x + 5 = 0$
We must isolate $x$ using standard algebraic operations.
This fraction can also be expressed as the decimal $-2.5$.
Graphing the linear equation $y = 2x + 5$ provides a visual confirmation of the zero. The line crosses the x-axis exactly at $x = -2.5$.
To ensure absolute mathematical rigor, we substitute $x = -\frac{5}{2}$ back into the original polynomial to verify that it yields $0$.
$p\left(-\frac{5}{2}\right) = 2\left(-\frac{5}{2}\right) + 5$
$p\left(-\frac{5}{2}\right) = -5 + 5$
$p\left(-\frac{5}{2}\right) = 0$
Since the result is exactly zero, the calculated value is verified as correct.
Final Solution: The zero of the polynomial $p(x) = 2x + 5$ is $x = -\frac{5}{2}$.
Solution:
We are given the quadratic polynomial:
$p(x) = 3x^2 - 1$
We must verify whether the given values, $x = -\frac{1}{\sqrt{3}}$ and $x = \frac{2}{\sqrt{3}}$, are zeroes of the polynomial.
[Theoretical Justification: By the definition of the zero of a polynomial, a real number $a$ is a zero of a polynomial $p(x)$ if and only if $p(a) = 0$. Therefore, we must substitute each given value of $x$ into the polynomial and evaluate the result.]
Substitute $x = -\frac{1}{\sqrt{3}}$ into the polynomial $p(x)$:
$p\left(-\frac{1}{\sqrt{3}}\right) = 3\left(-\frac{1}{\sqrt{3}}\right)^2 - 1$
First, apply the exponent to the fraction. The square of a negative number is positive, and the square of a square root removes the radical:
$\left(-\frac{1}{\sqrt{3}}\right)^2 = \frac{(-1)^2}{(\sqrt{3})^2} = \frac{1}{3}$
Now, substitute this back into the equation:
$p\left(-\frac{1}{\sqrt{3}}\right) = 3\left(\frac{1}{3}\right) - 1$
$p\left(-\frac{1}{\sqrt{3}}\right) = 1 - 1 = 0$
Since $p\left(-\frac{1}{\sqrt{3}}\right) = 0$, the value $x = -\frac{1}{\sqrt{3}}$ satisfies the condition.
Substitute $x = \frac{2}{\sqrt{3}}$ into the polynomial $p(x)$:
$p\left(\frac{2}{\sqrt{3}}\right) = 3\left(\frac{2}{\sqrt{3}}\right)^2 - 1$
Apply the exponent to the numerator and the denominator:
$\left(\frac{2}{\sqrt{3}}\right)^2 = \frac{2^2}{(\sqrt{3})^2} = \frac{4}{3}$
Substitute this back into the equation:
$p\left(\frac{2}{\sqrt{3}}\right) = 3\left(\frac{4}{3}\right) - 1$
$p\left(\frac{2}{\sqrt{3}}\right) = 4 - 1 = 3$
Since $p\left(\frac{2}{\sqrt{3}}\right) = 3 \neq 0$, the value $x = \frac{2}{\sqrt{3}}$ does not satisfy the condition.
To visualize this algebraically proven result, we can observe the graph of the parabola $y = 3x^2 - 1$. The zeroes of the polynomial correspond to the $x$-intercepts (where the graph crosses the horizontal axis, $y=0$).
As demonstrated by the graph, the point $x = -\frac{1}{\sqrt{3}}$ lies exactly on the $x$-axis (making it a zero), whereas the point $x = \frac{2}{\sqrt{3}}$ maps to a $y$-value of $3$, confirming it is not a zero.
Final Solution: $x = -\frac{1}{\sqrt{3}}$ is a zero of the polynomial $p(x) = 3x^2 - 1$, whereas $x = \frac{2}{\sqrt{3}}$ is not a zero of the polynomial.
Solution:
We are given the linear polynomial:
$p(x) = 3x$
Theoretical Definition: The "zero" or "root" of a polynomial $p(x)$ is defined as any real or complex number $c$ such that when $x$ is replaced by $c$, the value of the polynomial evaluates to zero. Mathematically, $c$ is a zero if and only if $p(c) = 0$ [Per the Fundamental Theorem of Algebra and the Factor Theorem].
To find the zero of the polynomial, we must equate the polynomial expression to zero. This transforms our polynomial expression into an algebraic equation.
$p(x) = 0$
Substituting the given expression for $p(x)$:
$3x = 0$
We now solve for the variable $x$. The term $3x$ represents the product of the constant $3$ and the variable $x$.
To isolate $x$, we apply the Multiplicative Property of Equality, dividing both sides of the equation by the coefficient $3$:
$\frac{3x}{3} = \frac{0}{3}$
Since any non-zero number dividing zero results in zero [Per the Zero Product Property and properties of real numbers]:
$x = 0$
To ensure absolute mathematical rigor, we verify the solution by substituting $x = 0$ back into the original polynomial $p(x)$:
$p(0) = 3(0)$
$p(0) = 0$
Because the polynomial evaluates to $0$ when $x = 0$, the solution is verified as correct.
Geometrically, the zero of a polynomial with real coefficients corresponds to the $x$-coordinate of the point where the graph of the function $y = p(x)$ intersects the $x$-axis. For $y = 3x$, this is a straight line passing through the origin.
As demonstrated in the Cartesian plane above, the line $y = 3x$ intersects the $x$-axis exactly at the origin $(0,0)$, visually confirming that the zero of the polynomial is $0$.
Final Solution: The zero of the polynomial $p(x) = 3x$ is $x = 0$.
Solution:
We are given the linear polynomial:
$p(x) = 3x - 2$
[Per the definition of the zero of a polynomial, a real number $a$ is a zero of a polynomial $p(x)$ if and only if $p(a) = 0$. Geometrically, this corresponds to the x-coordinate of the point where the graph of the polynomial intersects the x-axis.]
To find the zero of the given polynomial, we must set the polynomial expression equal to zero. This transforms our polynomial into a linear equation.
$p(x) = 0$
$3x - 2 = 0$
We now solve for $x$ using standard algebraic manipulation [By the properties of equality].
To ensure absolute mathematical rigor, we substitute $x = \frac{2}{3}$ back into the original polynomial to verify that it evaluates to zero.
$p\left(\frac{2}{3}\right) = 3\left(\frac{2}{3}\right) - 2$
$p\left(\frac{2}{3}\right) = 2 - 2$
$p\left(\frac{2}{3}\right) = 0$
[Since the evaluation yields exactly zero, the calculated root is verified as correct.]
The graph of the linear polynomial $y = 3x - 2$ is a straight line. The zero of the polynomial is the exact point where this line crosses the x-axis (where $y = 0$). As calculated, this intersection occurs at the coordinate $\left(\frac{2}{3}, 0\right)$.
Final Solution: The zero of the polynomial $p(x) = 3x - 2$ is $x = \frac{2}{3}$.
Solution:
We are tasked with verifying whether the given value of $x$ is a zero (or root) of the provided linear polynomial. The given parameters are:
[Theoretical Justification: By the fundamental definition of polynomials, a real number $c$ is considered a "zero" of a polynomial $p(x)$ if and only if evaluating the polynomial at $x = c$ yields a result of zero. Mathematically, this is expressed as $p(c) = 0$.]
To test the condition $p(c) = 0$, we substitute $x = \frac{1}{2}$ into the polynomial $p(x)$.
$p\left(\frac{1}{2}\right) = 2\left(\frac{1}{2}\right) + 1$
Next, we perform the arithmetic operations following the standard order of operations (PEMDAS/BODMAS).
First, multiply the terms:
$2 \times \frac{1}{2} = 1$
Now, substitute this product back into the expression:
$p\left(\frac{1}{2}\right) = 1 + 1$
$p\left(\frac{1}{2}\right) = 2$
We must now compare our evaluated result with the required condition for a zero.
$p\left(\frac{1}{2}\right) = 2 \neq 0$
[Since the polynomial evaluates to $2$ rather than $0$, the value $x = \frac{1}{2}$ fails the condition $p(c) = 0$.]
Geometrically, the zeroes of a polynomial $p(x)$ correspond to the $x$-intercepts of its graph $y = p(x)$. The graph below plots the linear function $y = 2x + 1$. Notice that the true zero occurs where the line crosses the x-axis at $x = -\frac{1}{2}$, whereas evaluating at $x = \frac{1}{2}$ yields a y-coordinate of $2$.
Because the evaluation of the polynomial at the given value does not result in zero, the value is not a root of the equation.
Final Solution: No, $x = \frac{1}{2}$ is not a zero of the polynomial $p(x) = 2x + 1$, because $p\left(\frac{1}{2}\right) = 2 \neq 0$.
Solution:
We are given the linear polynomial:
$p(x) = x + 5$
The zero (or root) of a polynomial $p(x)$ is defined as the real number $c$ such that $p(c) = 0$. [Per the Fundamental Theorem of Algebra and basic polynomial theory, a linear polynomial of degree 1 will have exactly one real zero].
To find the zero, we equate the polynomial to zero:
$x + 5 = 0$
Subtracting $5$ from both sides of the equation [By the Subtraction Property of Equality]:
$x = 0 - 5$
$x = -5$
Substitute $x = -5$ back into the original polynomial to ensure the condition $p(x) = 0$ is rigorously satisfied:
$p(-5) = (-5) + 5$
$p(-5) = 0$
The result is verified.
Geometrically, the zero of a polynomial represents the x-coordinate of the point where the graph of the function $y = p(x)$ intersects the x-axis (the line where $y = 0$). As shown in the Cartesian plane below, the line $y = x + 5$ crosses the x-axis exactly at the coordinate point $(-5, 0)$.
Final Solution: The zero of the polynomial $p(x) = x + 5$ is $x = -5$.
Solution:
We are given the following linear polynomial in one variable:
$p(x) = 5x - \pi$
We are tasked with verifying whether the following specific value of $x$ is a zero (root) of the polynomial:
$x = \frac{4}{5}$
By the fundamental definition of the Zero of a Polynomial [Factor Theorem corollary], a real number $a$ is considered a zero of a polynomial $p(x)$ if and only if evaluating the polynomial at $x = a$ yields exactly zero. Mathematically, this is expressed as:
$p(a) = 0$
Therefore, to verify if $x = \frac{4}{5}$ is a zero, we must substitute $x = \frac{4}{5}$ into $p(x)$ and determine if the resulting value is equal to $0$.
Substitute $x = \frac{4}{5}$ into the polynomial $p(x)$:
$p\left(\frac{4}{5}\right) = 5\left(\frac{4}{5}\right) - \pi$
Perform the multiplication. The factor of $5$ in the numerator and the denominator cancel each other out:
$p\left(\frac{4}{5}\right) = 4 - \pi$
We must now evaluate the expression $4 - \pi$.
Because $\pi$ is strictly less than $4$ (and is irrational), the difference $4 - \pi$ evaluates to a non-zero irrational number:
$4 - \pi \approx 4 - 3.14159 = 0.85841 \neq 0$
| Evaluated Point ($x$) | Polynomial Expression $p(x)$ | Resulting Value | Is $p(x) = 0$? |
|---|---|---|---|
| $x = \frac{\pi}{5}$ (Actual Zero) | $5\left(\frac{\pi}{5}\right) - \pi$ | $0$ | Yes |
| $x = \frac{4}{5}$ (Tested Point) | $5\left(\frac{4}{5}\right) - \pi$ | $4 - \pi \approx 0.858$ | No |
Graphically, the zeroes of a polynomial $p(x)$ correspond to the $x$-intercepts of the graph $y = p(x)$. The graph below plots the linear function $y = 5x - \pi$. The true zero is located at $x = \frac{\pi}{5} \approx 0.628$, while our tested point $x = \frac{4}{5} = 0.8$ clearly yields a positive $y$-value, proving it does not intersect the $x$-axis at this coordinate.
Final Solution: Since $p\left(\frac{4}{5}\right) = 4 - \pi \neq 0$, the value $x = \frac{4}{5}$ is NOT a zero of the polynomial $p(x) = 5x - \pi$.
Solution:
We are given the quadratic polynomial:
$p(x) = x^2 - 1$
We must verify whether the given values, $x = 1$ and $x = -1$, are zeroes of the polynomial $p(x)$.
Theoretical Justification: [Per the Definition of a Zero of a Polynomial], a real number $c$ is considered a zero (or root) of a polynomial $p(x)$ if and only if evaluating the polynomial at $x = c$ yields zero. Mathematically, this is expressed as $p(c) = 0$. Furthermore, [By the Factor Theorem], if $p(c) = 0$, then $(x - c)$ is a factor of the polynomial.
To determine if $x = 1$ is a zero, we substitute $x = 1$ into the polynomial $p(x)$:
Conclusion for $x = 1$: Since the evaluation results in exactly $0$, $x = 1$ is a verified zero of the polynomial $p(x)$.
Next, we substitute $x = -1$ into the polynomial $p(x)$:
Conclusion for $x = -1$: Since the evaluation results in exactly $0$, $x = -1$ is also a verified zero of the polynomial $p(x)$.
In coordinate geometry, the real zeroes of a polynomial $p(x)$ correspond precisely to the $x$-intercepts of the graph of the equation $y = p(x)$. By plotting the parabola $y = x^2 - 1$, we can visually confirm that the curve intersects the $x$-axis at exactly $x = -1$ and $x = 1$.
We can also verify the zeroes by factoring the polynomial completely. The expression $x^2 - 1$ is a classic "Difference of Squares", which follows the algebraic identity $a^2 - b^2 = (a - b)(a + b)$.
$p(x) = x^2 - 1^2$
$p(x) = (x - 1)(x + 1)$
To find the zeroes, we set $p(x) = 0$:
$(x - 1)(x + 1) = 0$
[By the Zero Product Property], if the product of two factors is zero, at least one of the factors must be zero:
This algebraic derivation perfectly matches our initial substitution method.
Final Solution: Yes, both $x = 1$ and $x = -1$ are verified zeroes of the polynomial $p(x) = x^2 - 1$.
Solution:
We are given the polynomial function:
$p(x) = (x + 1)(x - 2)$
We must verify whether the given values, $x = -1$ and $x = 2$, are zeroes of the polynomial.
[By the Fundamental Definition of a Zero of a Polynomial: A real number $a$ is a zero of a polynomial $p(x)$ if and only if evaluating the polynomial at $x = a$ yields zero, i.e., $p(a) = 0$.]
To determine if $x = -1$ is a zero, we substitute $-1$ for every instance of $x$ in the polynomial $p(x)$.
Since $p(-1) = 0$, we mathematically confirm that $x = -1$ is a zero of the polynomial $p(x)$.
Next, we apply the same substitution methodology for $x = 2$.
Since $p(2) = 0$, we mathematically confirm that $x = 2$ is also a zero of the polynomial $p(x)$.
The polynomial $p(x) = (x + 1)(x - 2)$ expands to the quadratic form $p(x) = x^2 - x - 2$. Geometrically, the zeroes of a polynomial correspond to the $x$-intercepts of its graph. The precise Cartesian plot below demonstrates the parabola intersecting the $x$-axis exactly at the coordinates $(-1, 0)$ and $(2, 0)$.
Final Solution: Yes, both $x = -1$ and $x = 2$ are zeroes of the polynomial $p(x) = (x + 1)(x - 2)$, as evaluating the polynomial at both values yields exactly $0$.
Solution:
We are given the following polynomial function and a specific value of the independent variable $x$:
Theoretical Foundation: [Per the Fundamental Theorem of Algebra and Polynomial Theory], a real number $c$ is defined as a "zero" (or root) of a polynomial $p(x)$ if and only if evaluating the polynomial at $x = c$ yields a result of zero. Mathematically, this is expressed as the condition: $p(c) = 0$.
To verify whether $x = 0$ is a zero of the given polynomial, we must substitute $0$ for every instance of $x$ in the function $p(x)$.
Substituting $x = 0$ into $p(x) = x^2$:
$p(0) = (0)^2$
Next, we evaluate the exponentiation. The square of zero is the product of zero multiplied by itself.
$p(0) = 0 \times 0$
$p(0) = 0$
[By the Zero Product Property], any real number multiplied by zero results in zero. Thus, the polynomial evaluates exactly to $0$.
Graphically, the zeroes of a polynomial correspond to the $x$-intercepts of its graph (the points where the graph crosses or touches the $x$-axis). The function $p(x) = x^2$ represents a standard upward-opening parabola. Because $x = 0$ yields $p(0) = 0$, the vertex of the parabola lies exactly at the origin $(0,0)$, confirming that $x=0$ is a root (specifically, a repeated root of multiplicity 2).
Because the evaluation of the polynomial at the given value satisfies the condition $p(0) = 0$, the indicated value is indeed a valid zero of the polynomial.
Final Solution: Yes, $x = 0$ is a zero of the polynomial $p(x) = x^2$.
Solution:
We are given the linear polynomial:
$p(x) = ax$
with the strict mathematical constraint that $a \neq 0$.
The "zero" (or root) of a polynomial is defined as the specific value of the independent variable $x$ that evaluates the polynomial to zero. [By the Fundamental Theorem of Algebra and the definition of polynomial roots].
To find this value, we must set the polynomial expression equal to zero:
$p(x) = 0$
$ax = 0$
To isolate $x$, we must divide both sides of the equation by the coefficient $a$. We are mathematically permitted to perform this operation strictly because the problem explicitly states the condition $a \neq 0$. [Per the Division Property of Equality, division by any non-zero real number is defined and preserves the equality].
$x = \frac{0}{a}$
Since zero divided by any non-zero number is strictly zero [Per the Zero Property of Division]:
$x = 0$
To ensure absolute analytical accuracy, we substitute our derived root, $x = 0$, back into the original polynomial function:
$p(0) = a(0)$
$p(0) = 0$
Because the polynomial evaluates to $0$, the value $x = 0$ is rigorously verified as the correct zero of the polynomial.
Geometrically, the zero of a polynomial represents the exact x-coordinate where the graph of the function intersects the x-axis (where $p(x) = 0$). For any non-zero real value of $a$, the linear equation $p(x) = ax$ represents a straight line passing directly through the origin $(0,0)$. The steepness and direction of the line depend on $a$, but the x-intercept remains invariant at the origin.
Final Solution: The zero of the polynomial $p(x) = ax$ (where $a \neq 0$) is $x = 0$.
Solution:
We are given a linear polynomial in one variable:
$p(x) = cx + d$
Where the given conditions are:
The "zero" (or root) of a polynomial is defined as the specific value of the variable $x$ for which the value of the entire polynomial becomes zero. [Per the Fundamental Theorem of Algebra and polynomial root definitions].
Therefore, to find the zero of $p(x)$, we must set the polynomial equal to zero:
$p(x) = 0$
Substitute the given expression for $p(x)$ into the equation:
$cx + d = 0$
To solve for $x$, we perform inverse operations to isolate the variable on one side of the equation.
First, subtract $d$ from both sides of the equation [By the Subtraction Property of Equality]:
$cx + d - d = 0 - d$
$cx = -d$
Next, divide both sides by $c$ [By the Division Property of Equality]. We are mathematically permitted to divide by $c$ because the initial problem explicitly stated the condition $c \neq 0$, thereby avoiding the undefined operation of division by zero:
$\frac{cx}{c} = \frac{-d}{c}$
$x = -\frac{d}{c}$
Geometrically, the polynomial $p(x) = cx + d$ represents a straight line on the Cartesian coordinate plane. The "zero" of the polynomial corresponds to the $x$-intercept of this line—the exact point where the graph crosses the $x$-axis (where $y = 0$).
As demonstrated in the coordinate geometry above, the line intersects the horizontal axis precisely at the coordinate $(-\frac{d}{c}, 0)$.
To verify the accuracy of our derived zero, we substitute $x = -\frac{d}{c}$ back into the original polynomial $p(x)$:
$p\left(-\frac{d}{c}\right) = c\left(-\frac{d}{c}\right) + d$
$p\left(-\frac{d}{c}\right) = -d + d$
$p\left(-\frac{d}{c}\right) = 0$
Since the polynomial evaluates to $0$, the root is mathematically verified.
Final Solution: The zero of the polynomial $p(x) = cx + d$ is $x = -\frac{d}{c}$.
Solution:
Let the given mathematical expression be defined as a polynomial function $P(x)$.
$P(x) = 5x - 4x^2 + 3$
[Per the standard form of a polynomial, it is conventionally written in descending order of the degree of its terms. Rearranging the terms yields:]
$P(x) = -4x^2 + 5x + 3$
We are required to evaluate the polynomial at the specific coordinate $x = 0$. This process involves substituting the value $0$ for every instance of the variable $x$ in the polynomial expression.
$P(0) = -4(0)^2 + 5(0) + 3$
Apply the standard order of operations [PEMDAS/BODMAS: evaluating exponents first, followed by multiplication, and finally addition].
| Polynomial Term | Substitution ($x = 0$) | Evaluated Value |
|---|---|---|
| $-4x^2$ | $-4(0)^2 = -4(0)$ | $0$ |
| $5x$ | $5(0)$ | $0$ |
| $+3$ (Constant Term) | $+3$ | $3$ |
Summing the evaluated terms:
$P(0) = 0 + 0 + 3$
$P(0) = 3$
Geometrically, evaluating any polynomial $P(x)$ at $x = 0$ yields the y-intercept of its graph. The constant term of the polynomial represents the exact point where the curve crosses the y-axis. For the quadratic function $P(x) = -4x^2 + 5x + 3$, the graph is a downward-opening parabola that intersects the y-axis at the coordinate $(0, 3)$.
Final Solution: The value of the polynomial $5x - 4x^2 + 3$ at $x = 0$ is 3.
Solution:
We are tasked with evaluating a given polynomial at a specific value of its variable. Let the given polynomial be denoted as $P(x)$.
The polynomial is defined as:
$P(x) = 5x - 4x^2 + 3$
For rigorous mathematical analysis, it is standard practice to rewrite the polynomial in descending order of its degree [Per the standard form of a polynomial $ax^2 + bx + c$]:
$P(x) = -4x^2 + 5x + 3$
We must find the value of the polynomial at $x = -1$. This requires substituting $-1$ for every instance of the variable $x$ within the function $P(x)$.
$P(-1) = -4(-1)^2 + 5(-1) + 3$
According to the fundamental order of operations [PEMDAS/BODMAS], we must evaluate the exponent before performing multiplication.
The square of a negative number is positive [Since $(-a) \times (-a) = a^2$]:
$(-1)^2 = (-1) \times (-1) = 1$
Substituting this back into our equation yields:
$P(-1) = -4(1) + 5(-1) + 3$
Next, we perform the scalar multiplications for each term:
Substituting these products back into the polynomial expression:
$P(-1) = -4 - 5 + 3$
Finally, we perform addition and subtraction from left to right to find the scalar value of the polynomial.
Combine the negative terms:
$-4 - 5 = -9$
Add the constant term:
$P(-1) = -9 + 3$
$P(-1) = -6$
To provide a comprehensive understanding, the polynomial $P(x) = -4x^2 + 5x + 3$ represents a downward-opening parabola [Because the leading coefficient $a = -4$ is less than zero]. Evaluating the polynomial at $x = -1$ corresponds to finding the $y$-coordinate of the point on this curve where the $x$-coordinate is $-1$. As calculated, this point exists exactly at $(-1, -6)$.
Final Solution: The value of the polynomial $5x - 4x^2 + 3$ at $x = -1$ is $-6$.
Solution:
We are given a linear polynomial in one variable, $x$, defined as:
$p(x) = 3x + 1$
We are tasked with verifying whether the specific value $x = -\frac{1}{3}$ is a zero of this polynomial.
[Per the foundational definition in polynomial algebra, a real number $a$ is considered a zero (or root) of a polynomial $p(x)$ if and only if evaluating the polynomial at $x = a$ yields a result of zero. Mathematically, this is expressed as $p(a) = 0$.]
To test the condition $p(a) = 0$, we substitute $x = -\frac{1}{3}$ into the polynomial equation $p(x)$.
$p\left(-\frac{1}{3}\right) = 3\left(-\frac{1}{3}\right) + 1$
Next, we perform the multiplication operation. [By the properties of rational numbers, multiplying an integer by a fraction involves multiplying the integer by the numerator and dividing by the denominator].
$3 \times \left(-\frac{1}{3}\right) = \frac{3 \times -1}{3} = -1$
Substituting this product back into the polynomial expression:
$p\left(-\frac{1}{3}\right) = -1 + 1$
Evaluating the arithmetic sum:
$p\left(-\frac{1}{3}\right) = 0$
Because the polynomial evaluates exactly to $0$, the condition for $x = -\frac{1}{3}$ being a zero of the polynomial is strictly satisfied.
Geometrically, the zero of a linear polynomial $p(x) = mx + c$ corresponds to the x-intercept of the line $y = mx + c$ on a Cartesian coordinate plane. The graph below demonstrates the line $y = 3x + 1$ intersecting the x-axis precisely at the coordinate $\left(-\frac{1}{3}, 0\right)$.
Final Solution: Yes, $x = -\frac{1}{3}$ is a zero of the polynomial $p(x) = 3x + 1$ because $p\left(-\frac{1}{3}\right) = 0$.
Solution:
We are given a polynomial in a single variable, $x$. Let us define the polynomial as a function $P(x)$:
$P(x) = 5x - 4x^2 + 3$
The objective is to evaluate this polynomial at the specific domain value $x = 2$. [Per the fundamental theorem of polynomial evaluation, finding the value of a polynomial at a given point requires the direct substitution of that point into the variable, followed by simplification according to the standard order of operations (PEMDAS/BODMAS)].
Substitute $x = 2$ into every instance of $x$ within the polynomial $P(x)$:
$P(2) = 5(2) - 4(2)^2 + 3$
According to the order of operations, exponentiation must be resolved before multiplication. We evaluate the quadratic term $(2)^2$:
$2^2 = 2 \times 2 = 4$
Substituting this back into the equation yields:
$P(2) = 5(2) - 4(4) + 3$
Next, perform the scalar multiplications for both the linear and quadratic terms:
Updating the polynomial expression:
$P(2) = 10 - 16 + 3$
Finally, evaluate the arithmetic expression from left to right:
$P(2) = (10 - 16) + 3$
$P(2) = -6 + 3$
$P(2) = -3$
The polynomial $P(x) = -4x^2 + 5x + 3$ represents a downward-opening parabola [since the leading coefficient $a = -4$ is less than zero]. Evaluating the polynomial at $x = 2$ corresponds to finding the $y$-coordinate of the point on this parabola where the $x$-coordinate is $2$. As calculated, this point exists exactly at $(2, -3)$ on the Cartesian plane.
Final Solution: The value of the polynomial $5x - 4x^2 + 3$ at $x = 2$ is $-3$.
Solution:
We are tasked with finding the zero of the following linear polynomial:
$p(x) = x - 5$
The zero (or root) of a polynomial $p(x)$ is defined as the specific real value of the variable $x$ for which the polynomial evaluates to zero. [Per the fundamental definition of polynomial roots]. Therefore, to find the zero, we must set the polynomial equal to zero:
$p(x) = 0$
Substituting the given algebraic expression for $p(x)$ into our equation, we obtain:
$x - 5 = 0$
To isolate the variable $x$ and solve the linear equation, we add $5$ to both sides of the equation [Per the Addition Property of Equality, which states that adding the same number to both sides of an equation maintains its balance]:
$x - 5 + 5 = 0 + 5$
$x = 5$
To ensure absolute mathematical accuracy, we verify the solution by substituting $x = 5$ back into the original polynomial to check if it yields zero:
$p(5) = (5) - 5$
$p(5) = 0$
Since the evaluation results in exactly zero, $x = 5$ is confirmed as the correct zero of the polynomial.
Geometrically, the zero of a polynomial with real coefficients corresponds to the $x$-coordinate of the point where the graph of the function $y = p(x)$ intersects the $x$-axis (where $y = 0$). For the linear function $y = x - 5$, the $x$-intercept occurs exactly at the Cartesian coordinate $(5, 0)$.
Final Solution: The zero of the polynomial $p(x) = x - 5$ is $x = 5$.