default_background

Find the best tutors and institutes for Class 10 Tuition

Find Best Class 10 Tuition

Please select a Category.

Please select a Locality.

No matching category found.

No matching Locality found.

Q4(iii):
Expand each of the following, using suitable identities: (iii) $(–2x + 3y + 2z)^2$

Solution :

Given Expression & Algebraic Identity

We are tasked with expanding the following trinomial squared:

$(–2x + 3y + 2z)^2$

To expand this expression systematically, we utilize the standard algebraic identity for the square of a trinomial [Derived from the distributive property of multiplication over addition]:

$(a + b + c)^2 = a^2 + b^2 + c^2 + 2ab + 2bc + 2ca$

Step 1: Variable Mapping

By comparing the given expression $(–2x + 3y + 2z)^2$ with the standard identity $(a + b + c)^2$, we establish the following one-to-one correspondence for the terms:

  • $a = -2x$
  • $b = 3y$
  • $c = 2z$

Note: It is critical to include the negative sign in the assignment of $a$ to ensure the cross-terms are calculated with the correct parity.

Step 2: Substitution into the Identity

Substituting the mapped variables into the expanded form of the identity yields:

$(-2x + 3y + 2z)^2 = (-2x)^2 + (3y)^2 + (2z)^2 + 2(-2x)(3y) + 2(3y)(2z) + 2(2z)(-2x)$

Step 3: Term-by-Term Expansion & Simplification

We now evaluate each term individually, applying the rules of exponents [$(xy)^n = x^n y^n$] and the rules of signed multiplication:

Component Calculation Result
$a^2$ $(-2x) \cdot (-2x)$ $4x^2$
$b^2$ $(3y) \cdot (3y)$ $9y^2$
$c^2$ $(2z) \cdot (2z)$ $4z^2$
$2ab$ $2 \cdot (-2x) \cdot (3y)$ $-12xy$
$2bc$ $2 \cdot (3y) \cdot (2z)$ $12yz$
$2ca$ $2 \cdot (2z) \cdot (-2x)$ $-8zx$

Step 4: Final Aggregation

Combining all the simplified terms from Step 3 into a single polynomial expression:

$4x^2 + 9y^2 + 4z^2 - 12xy + 12yz - 8zx$


Geometric Visualization of the Identity

The algebraic identity $(a+b+c)^2$ can be geometrically proven by calculating the area of a square with side length $(a+b+c)$. The total area is the sum of the 9 smaller rectangular regions, which perfectly mirrors our algebraic expansion.

a b c a b c ab ac ab bc ac bc

Final Solution: The expanded form of $(-2x + 3y + 2z)^2$ is $4x^2 + 9y^2 + 4z^2 - 12xy + 12yz - 8zx$.


More Questions from Class 9 Mathematics Polynomials EXERCISE 2.4


CBSE Solutions for Class 9 Mathematics Polynomials


Chapters in CBSE - Class 9 Mathematics


Top Tutors who teach Polynomials

(203)
Top Tutor
locationImg Venkatraman Nagar Chennai, Chennai
experience 10 yrs of Exp students 27 students
greenClock 3790 hrs of classes completed
rsIcon 320 per hour
Expereinced Tutor for class 9- class 12 on maths and sxience subjects
Online Classes Online Classes
regularClasses Tutor's home

im having good experince in teaching with make them understand the concepts better

Amudha

Classes are much interactive so useful to assess the students understanding capacity during the class itself.

Skills: Mathematics , Science
Also teaches: Class 11 Tuition, Class 9 Tuition and more

(32)
Top Tutor
locationImg Electronic City Electronics City Phase 1, Bangalore
experience 15 yrs of Exp students 5 students
greenClock 39 hrs of classes completed
rsIcon 1000 per hour
Teacher With 15 Years of Experience
Online Classes Online Classes

Ph.D enrolled, M.Tech(Electrical eng). Over 15 years of experience in teaching at different Engineering colleges and tutoring across different boards including CBSE, ICSE, IGCSE, IBDP, Level AS/A in Mathematics & Science. Approachable to students & succeeded to boost their fundamental knowledge.

Akhil

Ms. Dipika always ensures that students are thorough with the concepts and discourages mugging the formulae. She is chill with students; she actively helps and encourages students to perform their best rather than nagging them about a poor performance. Her teaching methods are simple, effective and logical. It helps build a strong conceptual foundation for advanced topics. Overall, Ms. Dipika is the perfect Maths tutor!

Skills: Mathematics
Also teaches: Class 6 Tuition, Class 9 Tuition and more

Deepak Joshi Class 10 Tuition trainer in Bangalore
(48)
Top Tutor
locationImg Ashok Nagar D' Souza Layout, Bangalore
experience 10 yrs of Exp students 25 students
greenClock 770 hrs of classes completed
rsIcon 600 per hour
Ph.D. Candidate | M.Sc. (Mathematics) | Former Faculty at BYJU'S (7 Years) & DPS Gurgaon (3 Years)
Online Classes Online Classes

10+ years of experience teaching Mathematics for Grades 10 to 12th • Consistent record of 100% academic results • Very friendly and supportive learning environment • Encourages students to ask questions freely and confidently • Strong focus on conceptual clarity and problem-solving skills • Helps students build confidence and excel in Mathematics • Fee Structure for One-to-One Classes: ₹700 per hour • Group Classes: ₹4,000 per month.

Pratima Dixit

Sir clears all my doubts he makes difficult concepts easy to understand he takes Previous year questions which makes it easier to prepare

Skills: Mathematics
Also teaches: Class 9 Tuition, Class 11 Tuition and more

locationImg Indirapuram, Ghaziabad
experience 8 yrs of Exp students 3 students
rsIcon 300 per hour
An tutor with 10year+ experience
Online Classes Online Classes
homeTutions Student's Home

I am a teacher of maths and science, having a experience of 8+ years in teaching, done my schooling from CBSe board and degree from IP university.

Skills: Mathematics , Science
Also teaches: Class 11 Tuition, Class 8 Tuition and more

(11)
Top Tutor
locationImg Beta I Block E, Noida
experience 5 yrs of Exp students 1 student
rsIcon 400 per hour
Best Education at best place unifyclasses.
Online Classes Online Classes
homeTutions Student's Home
regularClasses Tutor's home

Dear Parents and students, I am Amit, We provide home-based tuition for subjects and we also do professional coaching for NEET/IIT-JEE and other competitive exams. We have experienced tutors in all the fields and subjects. We also provide demo class free of cost. We do online as well as offline mode of teaching...

Skills: Mathematics , Physics and more

Find more Tutor for Polynomials in your City


Other Subjects in CBSE - Class 9

Worksheet Icon

Download free CBSE - Class 9 Mathematics Polynomials EXERCISE 2.4 worksheets

Download Now

Find Best Class 10 Tuition ?

Find Now »