CBSE · NCERT · Class 8 Maths · Chapter 8

NCERT Solutions: Class 8 Maths Chapter 8 - Algebraic Expressions and Identities

7 textbook Q&A7 verifiedFree Content

Chapter-wise NCERT intext questions and exercise answers for Algebraic Expressions and Identities, grounded in the official textbook.

Questions are taken verbatim from the NCERT textbook; answers were grounded against the chapter's content during generation. Items needing review are marked.
Sections in this chapter
Exercises 7
Your Progress - Chapter 80% complete
1Exercises7 questions
Q.1Add $7xy+5yz-3zx$, $4yz+9zx-4y$ and $-3xz+5x-2xy$.v
Solution

Combine like terms: $xy$: $7-2=5$; $yz$: $5+4=9$; $zx$: $-3+9-3=3$.

Answer:

$5xy+9yz+3zx-4y+5x$.

Q.2Subtract $5a^2-4b^2+3ab$ from $8a^2+2b^2-6ab$.v
Solution

$(8a^2+2b^2-6ab)-(5a^2-4b^2+3ab)$.

Answer:

$3a^2+6b^2-9ab$.

Q.3Multiply $2x$ by $3x+4$.v
Solution

Use distributivity: $2x(3x)+2x(4)$.

Answer:

$6x^2+8x$.

Q.4Multiply $(x+3)(x+5)$.v
Solution

$x^2+5x+3x+15$.

Answer:

$x^2+8x+15$.

Q.5Use an identity to find $(99)^2$.v
Solution

$(100-1)^2=10000-200+1=9801$.

Answer:

$9801$.

Q.6Use an identity to find $(102)^2$.v
Solution

$(100+2)^2=10000+400+4=10404$.

Answer:

$10404$.

Q.7Expand $(a+b)^2$.v
Solution

$(a+b)(a+b)=a^2+ab+ab+b^2$.

Answer:

$a^2+2ab+b^2$.