NCERT Solutions For Class 7 Maths Chapter 12 Algebraic Expressions Exercise 12.2

Table of Contents

Class 7, Maths, Chapter 12, Exercise 12.2 Solutions

Q.1. Simplify combining like terms:

(i) 21b – 32 + 7b – 20b

(ii) – z² + 13z² – 5z + 7z³ – 15z

(iii) p – (p – q) – q – (q – p)

(iv) 3a – 2b – ab – (a – b + ab) + 3ab + b – a

(v) 5x²y – 5x² + 3yx² – 3y² + x² – y² + 8xy² – 3y²

(vi) (3y² + 5y – 4) – (8y – y² – 4)

Q.2. Add:

(i) 3mn, – 5mn, 8mn, – 4mn

(ii) t – 8tz, 3tz – z, z – t

(iii) – 7mn + 5, 12mn + 2, 9mn – 8, – 2mn – 3

(iv) a + b – 3, b – a + 3, a – b + 3

(v) 14x + 10y – 12xy – 13, 18 – 7x – 10y + 8xy, 4xy

(vi) 5m – 7n, 3n – 4m + 2, 2m – 3mn – 5

(vii) 4x²y, – 3xy², –5xy², 5x²y

(viii) 3p²q² – 4pq + 5, – 10 p²q², 15 + 9pq + 7p²q²

(ix) ab – 4a, 4b – ab, 4a – 4b

(x) x² – y² – 1, y² – 1 – x², 1 – x² – y²

Q.3. Subtract:

(i) –5y² from y²

(ii) 6xy from –12xy

(iii) (a – b) from (a + b)

(iv) a (b – 5) from b (5 – a)

(v) –m² + 5mn from 4m² – 3mn + 8

(vi) – x² + 10x – 5 from 5x – 10

(vii) 5a² – 7ab + 5b² from 3ab – 2a² – 2b²

(viii) 4pq – 5q² – 3p² from 5p² + 3q² – pq

Q.4. (a) What should be added to x²+ xy + y² to obtain 2x² + 3xy?

(b) What should be subtracted from 2a + 8b + 10 to get – 3a + 7b + 16?

Ans:

(a) What should be added to x²+ xy + y² to obtain 2x² + 3xy:

(b) What should be subtracted from 2a + 8b + 10 to get – 3a + 7b + 16

Q.5. What should be taken away from 3x² – 4y² + 5xy + 20 to obtain – x² – y² + 6xy + 20 ?

Q.6. (a) From the sum of 3x – y + 11 and – y – 11, subtract 3x – y – 11.

(b) From the sum of 4 + 3x and 5 – 4x + 2x², subtract the sum of 3x² – 5x and –x² + 2x + 5.

Ans:

(a) From the sum of 3x – y + 11 and – y – 11, subtract 3x – y – 11.

(b) From the sum of 4 + 3x and 5 – 4x + 2x², subtract the sum of 3x² – 5x and –x² + 2x + 5.

NCERT Solutions For Class 7 Maths, Chapter 12 Algebraic Expressions (All Exercises)

Class 7, Maths, Chapter 12, Algebraic Expressions

Class 7, Maths, Chapter 12, Algebraic Expressions, Exercise 12.1

Class 7, Maths, Chapter 12, Algebraic Expressions, Exercise 12.2 ← You are here

Class 7, Maths, Chapter 12, Algebraic Expressions, Exercise 12.3

Class 7, Maths, Chapter 12, Algebraic Expressions, Exercise 12.4