Table of Contents

Toggle## Class 7, Maths, Chapter 12, Exercise 12.2 Solutions

**Q.1. Simplify combining like terms:**

**(i) 21b – 32 + 7b – 20b**

**(ii) – z ^{2} + 13z^{2} – 5z + 7z^{3} – 15z**

**(iii) p – (p – q) – q – (q – p)**

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

**(v) 5x ^{2}y – 5x^{2} + 3yx^{2} – 3y^{2} + x^{2} – y^{2} + 8xy^{2} – 3y^{2}**

**(vi) (3y ^{2} + 5y – 4) – (8y – y^{2} – 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) 4x ^{2}y, – 3xy^{2}, –5xy^{2}, 5x^{2}y**

**(viii) 3p ^{2}q^{2} – 4pq + 5, – 10 p^{2}q^{2}, 15 + 9pq + 7p^{2}q^{2}**

**(ix) ab – 4a, 4b – ab, 4a – 4b**

**(x) x ^{2} – y^{2} – 1, y^{2} – 1 – x^{2}, 1 – x^{2} – y^{2}**

**Q.3. Subtract:**

**(i) –5y ^{2} from y^{2}**

**(ii) 6xy from –12xy**

**(iii) (a – b) from (a + b)**

**(iv) a (b – 5) from b (5 – a)**

**(v) –m ^{2} + 5mn from 4m^{2} – 3mn + 8**

**(vi) – x ^{2} + 10x – 5 from 5x – 10**

**(vii) 5a ^{2} – 7ab + 5b^{2} from 3ab – 2a^{2} – 2b^{2}**

**(viii) 4pq – 5q ^{2} – 3p^{2} from 5p^{2} + 3q^{2} – pq**

**Q.4. (a) What should be added to x ^{2}+ xy + y^{2} to obtain 2x^{2} + 3xy?**

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

**Ans:**

**(a) What should be added to x ^{2}+ xy + y^{2} to obtain 2x^{2} + 3xy:**

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

**Q.5. What should be taken away from 3x ^{2} – 4y^{2} + 5xy + 20 to obtain – x^{2} – y^{2} + 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 + 2x ^{2}, subtract the sum of 3x^{2} – 5x and –x^{2} + 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 + 2x ^{2}, subtract the sum of 3x^{2} – 5x and –x^{2} + 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**