**ML Aggarwal CBSE Solutions Class 7 Math 5th Chapter Algebraic Expressions Exercise 5.2**

**Exercise 5.2 Solution**

(1) 7x, -3x

(ii) 6x, -11x

(iii) -9x^{2}

(iv) 3ab^{2}, -5ab^{2}

(v) 1/2 pq, -1/3 pq

(vi) 5x^{3}y, -2/3 x^{3}y

**(2) Add:**

(i) 3x, -5x, 7x

(ii) 7xy, 2xy, -8xy

(iii) -2abc, 3abc, abc

(iv) 3mn, -5mn,8mn, -4mn

(v) 2x^{3}, 4x^{3}, -4x^{3}, -5x^{3}

**(3) Simplify the following combining like terms:**

(i) 21b – 32 + 7b – 20b

(ii) 12m^{2} – 9m + 5m – 4m^{2} – 7m + 10

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

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

(v) p – (p – q) – (q – p) – q

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

(vii) (3y^{2} + 5y – 4) – (8y – y^{2 }– 4)

**(4) Find the sum of the following algebraic expressions:**

(i) 5xy, -7xy, 7x^{2}

(ii) 4x^{2}y, -3xy^{2}, -5xy^{2}, 5x^{2}y

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

(iv) a + b – 3, b – a + 3, a – b + 3

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

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

(vii) 3x^{3} – 5x^{2} + 2x + 1, 3x – 2x^{2} – x^{3}

(viii) 7a^{2} – 5a + 2, 3a^{2} – 7, 2a + 9, 1 + 2a – 5a^{2}

**(5) Simplify the following:**

(i) 2x^{2} + 3y^{2} – 5xy + 5x^{2} – y^{2} + 6xy – 3x^{2}

(ii) 3xy^{2 }– 5x^{2}y + 7xy – 8xy^{2} – 4xy + 6x^{2}y

(iii) 5x^{4} – 7x^{2} + 8x – 1 + 3x^{3} – 9x^{2 }+ 7 – 3x^{4} + 11x -2 + 8x^{2}

**(6) Subtract:**

(i) -5y^{2} from y^{2}

(ii) – 7xy from -2xy

(iii) a(b – 5) from b(5 – a)

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

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

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

(vii) 7xy + 5x^{2} – 7y^{2} + 3 from 7x^{2} – 8xy + 3y^{2} – 5

(viii) 2x^{4} – 7x^{2} + 5x + 3 from x^{4} – 3x^{3} – 2x^{2} + 3

**(7) Subtract p – 2q + r from the sum of 10p – r and 5p + 2q.**

**(8) From the sum of 4 + 3x and 5 – 4x + 2x ^{2}, subtract the sum of 3x^{2} – 5x and –x^{2} + 2x + 5**

**Solution Number 1, 2, 3, 4, 5, 6, 7 & 8:**

**(9) What should be added to x ^{2} – y^{2} + 2xy to obtain x^{2} + y^{2} + 5xy?**

**(10) What should be subtracted from -7mn + 2m ^{2} + 3n^{2} to get m^{2 }+ 2mn + n^{2}?**

**(11) How much is y ^{4} – 12y^{2} + y + 14 greater than 17y^{3} + 34y^{2} – 51y + 68**

**(12) How much does 93p ^{2} – 55p + 4 exceeds 13p^{3 }– 5p^{2} + 17p – 90?**

**(13) What should be taken away from 3x ^{2} – 4y^{2} + 5xy + 20 to obtain – x^{2} – y^{2} + 6xy + 20?**

**Solution Number 9, 10, 11, 12 & 13:**

** (14) From the sum of 2y ^{2} + 3yz, y^{2 }– yz – z^{2} and yz + 2z^{2}, subtract the of 3y^{2 }– z^{2} and –y^{2} + yz + z^{2}**

**Solution Number 14:**