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CBSE - Class 11 Mathematics Linear Inequalities Worksheet
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Solution:
The given linear inequality is:
$\frac{x}{2} \ge \frac{5x-2}{3} - \frac{7x-3}{5}$
To simplify, identify the Least Common Multiple (LCM) of the denominators $2$, $3$, and $5$, which is $30$ [By the property of arithmetic operations on rational expressions]. Multiply both sides of the inequality by $30$:
$30 \cdot \left( \frac{x}{2} \right) \ge 30 \cdot \left( \frac{5x-2}{3} - \frac{7x-3}{5} \right)$
$15x \ge 10(5x - 2) - 6(7x - 3)$
Distribute the constants across the terms within the parentheses:
$15x \ge 50x - 20 - 42x + 18$ [By Distributive Property of Multiplication]
Combine like terms on the right-hand side:
$15x \ge (50x - 42x) + (-20 + 18)$
$15x \ge 8x - 2$
Subtract $8x$ from both sides of the inequality [Per the Addition Property of Inequality]:
$15x - 8x \ge -2$
$7x \ge -2$
Divide both sides by $7$:
$x \ge -\frac{2}{7}$
The solution in interval notation is $[-\frac{2}{7}, \infty)$. This indicates that all real numbers greater than or equal to $-\frac{2}{7}$ satisfy the original inequality.
Final Solution: $x \in \left[ -\frac{2}{7}, \infty \right)$
Solution:
Given the linear inequality: $x + \frac{x}{2} + \frac{x}{3} < 11$ [Per the property of algebraic summation of fractions]
To add the terms involving $x$, we identify the Least Common Multiple (LCM) of the denominators $\{1, 2, 3\}$, which is $6$. Rewriting the expression: $\frac{6x}{6} + \frac{3x}{6} + \frac{2x}{6} < 11$ [By the property of equivalent fractions]
Summing the numerators: $\frac{6x + 3x + 2x}{6} < 11$ $\frac{11x}{6} < 11$ [By the distributive property of multiplication $a(b+c) = ab + ac$]
To isolate $x$, we multiply both sides of the inequality by $6$: $11x < 11 \times 6$ $11x < 66$ [Per the Multiplication Property of Inequality: if $c > 0$, then $a < b \implies ac < bc$]
Divide both sides by $11$: $x < \frac{66}{11}$ $x < 6$ [Per the Division Property of Inequality: if $c > 0$, then $a < b \implies \frac{a}{c} < \frac{b}{c}$]
Since the inequality is strict ($<$), the value $6$ is excluded from the solution set. For all real $x$ such that $x < 6$: $x \in (-\infty, 6)$ [By the definition of open intervals in real numbers]
Final Solution: $x < 6$ or $x \in (-\infty, 6)$
Solution:
The given linear inequality is: $24x < 100$ [Per the property of inequalities, we can divide both sides by a positive number without changing the direction of the inequality sign.]
Divide both sides of the inequality by $24$:
$x < \frac{100}{24}$
Reducing the fraction by dividing the numerator and denominator by their greatest common divisor ($4$):
$x < \frac{25}{6}$
Converting to a decimal representation for clarity:
$x < 4.166...$
[By the definition of real number division and inequality properties.]
The problem specifies that $x$ must be a natural number ($x \in \mathbb{N}$).
Natural numbers are defined as the set of positive integers: $\{1, 2, 3, 4, 5, ...\}$.
We seek all natural numbers $x$ such that $x < 4.166...$.
Comparing the set of natural numbers against the upper bound:
Final Solution: The set of natural numbers satisfying the inequality is $\{1, 2, 3, 4\}$.
Solution:
Given the linear inequality: $3x + 8 > 2$
To isolate the term containing $x$, we subtract $8$ from both sides of the inequality [Per the Addition/Subtraction Property of Inequalities]: $3x + 8 - 8 > 2 - 8$ $3x > -6$
Next, we divide both sides by $3$. Since $3 > 0$, the direction of the inequality sign remains unchanged [Per the Multiplication/Division Property of Inequalities]: $\frac{3x}{3} > \frac{-6}{3}$ $x > -2$
We are tasked to find the solution set where $x$ must be an integer ($\mathbb{Z}$). The inequality $x > -2$ represents all real numbers strictly greater than $-2$. Within the domain of integers, this set includes every integer starting from the next consecutive integer after $-2$.
The set of integers $x$ such that $x > -2$ is given by: $S = \{ -1, 0, 1, 2, 3, 4, \dots \}$
By solving the algebraic inequality and restricting the domain to the set of integers, we identify that any integer greater than $-2$ satisfies the condition.
Final Solution: The solution set for $x$ is $\{x \in \mathbb{Z} : x > -2\}$, which is $\{-1, 0, 1, 2, 3, \dots \}$.
Solution:
Let the marks obtained by Ravi in the third unit test be represented by the variable $x$. The objective is to determine the minimum value of $x$ such that the average of the three test scores is at least 60 marks.
The given marks for the first two tests are $70$ and $75$. The arithmetic mean of three values is calculated as the sum of the values divided by the count of the values [Per the definition of Arithmetic Mean].
The condition "at least 60" is mathematically translated as $\geq 60$. Constructing the inequality based on the average formula:
$$\frac{70 + 75 + x}{3} \geq 60$$
To isolate $x$, we apply the properties of inequalities [Per the Multiplication Property of Inequality, where multiplying by a positive constant preserves the inequality sign]:
The solution $x \geq 35$ indicates that Ravi must score a minimum of 35 marks to achieve an average of 60.
| Test Component | Marks Obtained |
|---|---|
| Test 1 | 70 |
| Test 2 | 75 |
| Test 3 (Minimum) | 35 |
| Average | 60 |
Final Solution: Ravi must obtain a minimum of 35 marks in the third test to secure an average of at least 60 marks.
Solution:
The given linear inequality is:
$5x - 3 < 7$
To isolate the variable $x$, we apply the addition property of inequalities [Per the properties of inequalities, adding the same real number to both sides of an inequality does not change its direction].
Add $3$ to both sides:
$5x - 3 + 3 < 7 + 3$
$5x < 10$
To solve for $x$, divide both sides of the inequality by $5$. Since $5$ is a positive real number, the inequality sign remains unchanged [Per the multiplication/division property of inequalities, if $c > 0$, then $a < b \implies \frac{a}{c} < \frac{b}{c}$].
$\frac{5x}{5} < \frac{10}{5}$
$x < 2$
When $x$ is defined as a real number ($x \in \mathbb{R}$), the solution is the set of all real values strictly less than $2$. This corresponds to the interval $(-\infty, 2)$.
The solution set is represented on the real number line by an open circle at $2$ (indicating $2$ is excluded) and shading the region to the left.
Final Solution: $x \in (-\infty, 2)$
Solution:
Given the inequality:
$37 - (3x + 5) > 9x - 8(x - 3)$
Apply the distributive property to remove the parentheses [Per the Distributive Property of Multiplication over Addition/Subtraction]:
$37 - 3x - 5 > 9x - 8x + 24$
Combine constant terms and variable terms on each side of the inequality separately [By Arithmetic Simplification]:
Left Side: $(37 - 5) - 3x = 32 - 3x$
Right Side: $(9x - 8x) + 24 = x + 24$
The inequality becomes:
$32 - 3x > x + 24$
Add $3x$ to both sides of the inequality [Per the Addition Property of Inequalities]:
$32 > x + 3x + 24$
$32 > 4x + 24$
Subtract $24$ from both sides [Per the Subtraction Property of Inequalities]:
$32 - 24 > 4x$
$8 > 4x$
Divide both sides by the positive coefficient $4$ [Per the Division Property of Inequalities; since $4 > 0$, the inequality sign remains unchanged]:
$\frac{8}{4} > x$
$2 > x$
This is equivalent to stating $x < 2$.
Since the inequality is $x < 2$, the set of all real numbers $x$ satisfying this inequality is all values less than $2$.
Interval notation: $(-\infty, 2)$
Final Solution: $x \in (-\infty, 2)$
Solution:
Given the linear inequality in one variable:
$3x - 7 > 5x - 1$
To collect the variable $x$ on one side, subtract $3x$ from both sides of the inequality [Per the Addition/Subtraction Property of Inequalities, adding or subtracting the same value does not change the inequality sign].
$3x - 3x - 7 > 5x - 3x - 1$
$-7 > 2x - 1$
Add $1$ to both sides of the inequality to isolate the term containing $x$:
$-7 + 1 > 2x - 1 + 1$
$-6 > 2x$
Divide both sides by $2$ [Since $2 > 0$, the direction of the inequality remains unchanged per the Multiplication/Division Property of Inequalities].
$\frac{-6}{2} > \frac{2x}{2}$
$-3 > x$
The inequality $-3 > x$ can be rewritten as $x < -3$. In set-builder notation, the solution is $\{x : x \in \mathbb{R}, x < -3\}$. In interval notation, the solution set is $(-\infty, -3)$.
Final Solution: The solution set for the inequality $3x - 7 > 5x - 1$ is $x < -3$, represented in interval notation as $(-\infty, -3)$.
Solution:
We are provided with the following linear inequality in one variable $x$:
$2(2x + 3) - 10 < 6(x - 2)$
Distribute the constants on both sides of the inequality [Per the Distributive Property of Multiplication over Addition/Subtraction]:
$2(2x) + 2(3) - 10 < 6(x) - 6(2)$
$4x + 6 - 10 < 6x - 12$
Simplify the numerical terms on the left-hand side:
$4x - 4 < 6x - 12$
To isolate the variable $x$, subtract $4x$ from both sides [Per the Addition/Subtraction Property of Inequalities]:
$4x - 4x - 4 < 6x - 4x - 12$
$-4 < 2x - 12$
Add $12$ to both sides to isolate the term containing $x$:
$-4 + 12 < 2x$
$8 < 2x$
Divide both sides by $2$. Since $2 > 0$, the direction of the inequality remains unchanged [Per the Multiplication/Division Property of Inequalities]:
$\frac{8}{2} < \frac{2x}{2}$
$4 < x$
This is equivalent to $x > 4$.
The solution for the real value of $x$ is the interval $(4, \infty)$.
Final Solution: The solution set for the inequality $2 (2x + 3) – 10 < 6 (x – 2)$ is $x \in (4, \infty)$ or $x > 4$.
Solution:
Let the length of the shortest side of the triangle be $x$ cm, where $x > 0$. Based on the problem statement, we define the other two sides as follows:
[Per the definitions provided by the problem constraints]
The perimeter of a triangle is the sum of its three sides. The problem states that the perimeter is at least $61$ cm. Therefore:
$x + 3x + (3x - 2) \geq 61$
Combining like terms:
$7x - 2 \geq 61$
$7x \geq 63$
$x \geq 9$ [By the property of linear inequalities, dividing both sides by a positive number preserves the inequality sign]
For any triangle with sides $a, b, c$, the sum of any two sides must be strictly greater than the third side ($a + b > c$). Given sides are $x$, $3x$, and $3x-2$.
| Condition | Inequality Formulation | Result |
|---|---|---|
| $a + b > c$ | $x + (3x - 2) > 3x$ | $4x - 2 > 3x \implies x > 2$ |
| $a + c > b$ | $x + 3x > 3x - 2$ | $4x > 3x - 2 \implies x > -2$ |
| $b + c > a$ | $3x + (3x - 2) > x$ | $6x - 2 > x \implies 5x > 2 \implies x > 0.4$ |
[By the Triangle Inequality Theorem, all sides must satisfy these conditions simultaneously]
From Step 2, we found $x \geq 9$. From Step 3, the condition $x > 2$ must be satisfied for the triangle to exist. Since $9 > 2$, the value $x = 9$ satisfies all conditions of the problem.
Final Solution: The minimum length of the shortest side is 9 cm.
Solution:
Given the inequality:
$3(2 - x) \ge 2(1 - x)$
Apply the Distributive Property of Multiplication over Subtraction, $a(b - c) = ab - ac$ [Per the Distributive Law of Real Numbers]:
$3 \cdot 2 - 3 \cdot x \ge 2 \cdot 1 - 2 \cdot x$
$6 - 3x \ge 2 - 2x$
To collect variable terms on one side and constant terms on the other, add $3x$ to both sides of the inequality [Per the Addition Property of Inequalities]:
$6 - 3x + 3x \ge 2 - 2x + 3x$
$6 \ge 2 + x$
Subtract $2$ from both sides of the inequality to isolate $x$ [Per the Subtraction Property of Inequalities]:
$6 - 2 \ge 2 + x - 2$
$4 \ge x$
Rewriting the inequality for standard form: $x \le 4$.
Since the inequality is $x \le 4$, the solution includes all real numbers less than or equal to $4$. In interval notation, this is expressed as $(-\infty, 4]$.
| Notation Type | Representation |
|---|---|
| Set-Builder | $\{x \in \mathbb{R} : x \le 4\}$ |
| Interval | $(-\infty, 4]$ |
Final Solution: The solution set for $x$ is $x \le 4$, or in interval notation, $(-\infty, 4]$.
Solution:
Given the inequality: $5x - 3 > 3x - 5$
Our objective is to isolate the variable $x$ on one side of the inequality. [Per the properties of inequalities, we may add or subtract the same real number from both sides without changing the sign of the inequality].
Subtract $3x$ from both sides:
$5x - 3x - 3 > 3x - 3x - 5$
$2x - 3 > -5$
Add $3$ to both sides:
$2x - 3 + 3 > -5 + 3$
$2x > -2$
Divide both sides by $2$. [Per the Multiplication/Division Property of Inequalities, if a positive number is used to divide both sides, the inequality sign remains unchanged].
$\frac{2x}{2} > \frac{-2}{2}$
$x > -1$
The solution set $x > -1$ implies all real numbers strictly greater than $-1$. On a number line, this is represented by an open circle at $-1$ (to signify that $-1$ is not included) and a ray extending to the right towards positive infinity.
The interval notation for this solution is $x \in (-1, \infty)$.
Final Solution: $x > -1$ or $x \in (-1, \infty)$
Solution:
To solve the inequality $3(x - 1) \le 2(x - 3)$, we first apply the Distributive Property of Multiplication over subtraction, denoted as $a(b - c) = ab - ac$ [Per the Distributive Law of Real Numbers].
$3x - 3 \le 2x - 6$
To consolidate the variable $x$ on one side of the inequality, we subtract $2x$ from both sides of the inequality [Per the Addition Property of Inequalities: if $a \le b$, then $a - c \le b - c$].
$3x - 2x - 3 \le 2x - 2x - 6$
$x - 3 \le -6$
To solve for $x$, we add $3$ to both sides of the inequality [Per the Addition Property of Inequalities].
$x - 3 + 3 \le -6 + 3$
$x \le -3$
The solution set represents all real numbers less than or equal to $-3$. This is expressed in interval notation as $(-\infty, -3]$.
Given the domain is all real numbers ($x \in \mathbb{R}$), the inequality $x \le -3$ encompasses every point on the real number line starting from $-\infty$ up to and including $-3$.
| Representation Type | Mathematical Expression |
|---|---|
| Inequality | $x \le -3$ |
| Interval Notation | $(-\infty, -3]$ |
| Set-Builder Notation | $\{x : x \in \mathbb{R}, x \le -3\}$ |
Final Solution: The solution to the inequality $3(x - 1) \le 2(x - 3)$ is $x \le -3$, or in interval notation, $(-\infty, -3]$.
Solution:
Given the linear inequality: $3(1 - x) < 2(x + 4)$
Apply the distributive property of multiplication over subtraction and addition [$a(b \pm c) = ab \pm ac$]:
$3 - 3x < 2x + 8$
To collect all $x$ terms on one side, subtract $2x$ from both sides [Per the Addition Property of Inequality]:
$3 - 3x - 2x < 8$
$3 - 5x < 8$
Subtract $3$ from both sides [Per the Addition Property of Inequality]:
$-5x < 8 - 3$
$-5x < 5$
Divide both sides by $-5$. Note that dividing or multiplying an inequality by a negative number reverses the direction of the inequality sign [Per the Multiplicative Inverse Property of Inequality]:
$x > \frac{5}{-5}$
$x > -1$
The solution $x > -1$ indicates all real numbers greater than $-1$, excluding $-1$ itself. We represent this with a hollow circle at $-1$ and a shaded ray extending to the right.
Final Solution: The solution to the inequality is $x \in (-1, \infty)$, representing all real values strictly greater than $-1$.
Solution:
Given the linear inequality:
$\frac{3(x - 2)}{5} \le \frac{5(2 - x)}{3}$
To eliminate the denominators, calculate the Least Common Multiple (LCM) of $5$ and $3$, which is $15$. Multiply both sides of the inequality by $15$. [Per the Multiplication Property of Inequality, multiplying by a positive constant does not reverse the inequality sign].
$15 \times \left( \frac{3(x - 2)}{5} \right) \le 15 \times \left( \frac{5(2 - x)}{3} \right)$
Simplify the fractions by canceling common factors:
$3 \times 3(x - 2) \le 5 \times 5(2 - x)$
$9(x - 2) \le 25(2 - x)$
Apply the distributive law of multiplication over subtraction [$a(b - c) = ab - ac$]:
$9x - 18 \le 50 - 25x$
Collect all terms containing $x$ on the left side by adding $25x$ to both sides, and all constant terms on the right side by adding $18$ to both sides [Per the Addition Property of Inequality].
$9x + 25x \le 50 + 18$
$34x \le 68$
Divide both sides by $34$. Since $34 > 0$, the inequality sign remains unchanged [Per the Division Property of Inequality].
$x \le \frac{68}{34}$
$x \le 2$
The inequality $x \le 2$ includes all real numbers less than or equal to $2$. In interval notation, this is expressed as:
$x \in (-\infty, 2]$
Final Solution: x \in (-\infty, 2]
Solution:
The objective is to solve the linear inequality for real values of $x$:
$$\frac{x}{3} > \frac{x}{2} + 1$$
To solve for $x$, we collect all terms containing $x$ on the left-hand side of the inequality. We subtract $\frac{x}{2}$ from both sides [Per the Addition/Subtraction Property of Inequalities]:
$$\frac{x}{3} - \frac{x}{2} > 1$$
Find the Least Common Multiple (LCM) of the denominators $3$ and $2$, which is $6$. Convert the fractions to equivalent fractions with a denominator of $6$:
$$\frac{2x}{6} - \frac{3x}{6} > 1$$
Combine the fractions:
$$\frac{2x - 3x}{6} > 1$$
$$\frac{-x}{6} > 1$$
Multiply both sides of the inequality by $6$ [Per the Multiplication Property of Inequalities, since $6 > 0$, the inequality sign remains unchanged]:
$$-x > 6$$
Multiply both sides by $-1$. [Per the Multiplication Property of Inequalities, since we are multiplying by a negative number, the inequality sign must be reversed]:
$$x < -6$$
The solution set represents all real numbers strictly less than $-6$.
In interval notation, the set of all real numbers satisfying $x < -6$ is expressed as:
$$x \in (-\infty, -6)$$
Final Solution: The solution to the inequality is $x < -6$, or in interval notation, $x \in (-\infty, -6)$.
Solution:
Let the marks obtained by Sunita in the fifth examination be denoted by the variable $x$. The condition for receiving Grade 'A' is defined by the requirement that the arithmetic mean of the five examinations must be greater than or equal to 90.
The average is calculated as the sum of all marks divided by the total number of examinations ($n = 5$):
$\frac{87 + 92 + 94 + 95 + x}{5} \geq 90$ [Definition of Arithmetic Mean]
First, sum the known values in the numerator:
$87 + 92 + 94 + 95 = 368$
Substitute this back into the inequality:
$\frac{368 + x}{5} \geq 90$
To solve for $x$, multiply both sides of the inequality by 5. Since 5 is a positive constant, the direction of the inequality sign remains unchanged [Per the Multiplication Property of Inequalities]:
$368 + x \geq 90 \times 5$
$368 + x \geq 450$
Now, subtract 368 from both sides of the inequality [Per the Addition/Subtraction Property of Inequalities]:
$x \geq 450 - 368$
$x \geq 82$
The inequality $x \geq 82$ implies that for Sunita to maintain an average of 90 or more, her marks in the fifth examination must be at least 82. Since the maximum marks possible in the examination is 100, the solution set for $x$ is the interval $[82, 100]$.
Final Solution: The minimum marks that Sunita must obtain in the fifth examination to secure Grade ‘A’ is 82.
Solution:
Given the linear inequality: $5x - 3 < 7$.
To isolate the term involving $x$, we apply the addition property of inequality by adding $3$ to both sides of the expression [Per the Addition Property of Inequalities]:
$5x - 3 + 3 < 7 + 3$
$5x < 10$
To solve for $x$, we divide both sides of the inequality by $5$. Since $5 > 0$, the direction of the inequality sign remains unchanged [Per the Division Property of Inequalities for positive constants]:
$\frac{5x}{5} < \frac{10}{5}$
$x < 2$
The condition specifies that $x$ must be an integer ($\mathbb{Z}$). The set of all integers strictly less than $2$ includes all negative integers, zero, and positive integers up to $1$.
This can be represented as the set: $\{\dots, -3, -2, -1, 0, 1\}$.
Final Solution: The solution set for $x$ where $x$ is an integer is $\{\dots, -3, -2, -1, 0, 1\}$.
Solution:
Let the two consecutive odd positive integers be represented as $x$ and $x+2$.
We solve the inequality representing the sum constraint:
$x + x + 2 > 11$
$2x + 2 > 11$ [Algebraic Addition Property]
$2x > 9$ [Subtraction Property of Inequality]
$x > 4.5$ [Division Property of Inequality]
We analyze the constraint that both integers are smaller than 10:
$x + 2 < 10$
$x < 8$ [Subtraction Property of Inequality]
Combining the results from Step 2 and Step 3, we obtain the range for $x$:
$4.5 < x < 8$
Given that $x$ must be an odd positive integer [Given condition], we examine the integers within the interval $(4.5, 8)$:
| $x$ | $x+2$ | Pair $(x, x+2)$ | Sum ($2x+2$) |
|---|---|---|---|
| 5 | 7 | (5, 7) | 12 > 11 (True) |
| 7 | 9 | (7, 9) | 16 > 11 (True) |
Final Solution: The pairs of consecutive odd positive integers are (5, 7) and (7, 9).
Solution:
The given inequality is:
$-12x > 30$
To isolate the variable $x$, we divide both sides of the inequality by $-12$. [By the Property of Inequality: Dividing or multiplying both sides of an inequality by a negative number reverses the direction of the inequality sign].
$\frac{-12x}{-12} < \frac{30}{-12}$
Perform the division and reduce the fraction to its lowest terms:
$x < -\frac{30}{12}$
$x < -\frac{5}{2}$
$x < -2.5$
The problem specifies that $x$ must be a natural number ($\mathbb{N}$). The set of natural numbers is defined as $\mathbb{N} = \{1, 2, 3, 4, ...\}$.
We evaluate the condition $x < -2.5$ against the set of natural numbers:
As illustrated, the red region representing the solution $x < -2.5$ does not overlap with the natural numbers, which begin at $1$ on the positive side of the origin ($0$).
Final Solution: Since there are no natural numbers $x$ such that $x < -2.5$, the solution set is the empty set, denoted by $\emptyset$ or $\{\}$.