## Ex 11.5 Class 8 ML Aggarwal

Question 1.

Work out the following divisions:

(i) (35x + 28) ÷ (5x + 4)

(ii) 7p^{2}q^{2}(9r – 27) ÷ 63pq(r – 3)

Solution:

(i) (35x + 28) ÷ (5x + 4)

= \(\frac{7(5 x+4)}{(5 x+4)}=7\)

(ii) 7p^{2}q^{2}(9r – 27) ÷ 63pq(r – 3)

= \(\frac{7 p^{2} q^{2} \times 9(r-3)}{63 p q(r-3)}\)

= p^{2-1} q^{2-1} × 9 = 9pq

Question 2.

Divide as directed:

(i) 6(2x + 7) (5x – 3) ÷ 3(5x – 3)

(ii) 33pq (p + 3) (2q – 5) ÷ 11p (2q – 5)

Solution:

(i) 6(2x + 7) (5x – 3) ÷ 3(5x – 3)

= \(\frac{6(2 x+7)(5 x-3)}{3(5 x-3)}\) = 2(2x + 7)

(ii) 33pq (p + 3) (2q – 5) ÷ 11p (2q – 5)

= \(\frac{33 p q(p+3)(2 q-5)}{11 p(2 q-5)}\) = 3q(p + 3)

Question 3.

Factorise the expression and divide them as directed:

(i) (7x^{2} – 63x) ÷ 7(x – 3)

(ii) (3p^{2} + 17p + 10) ÷ (p + 5)

(iii) 10xy(14y^{2} + 43y – 21) ÷ 5x(7y – 3)

(iv) 12pqr(6p^{2} – 13pq + 6q^{2}) ÷ 6pq(2p – 3q)

Solution:

(i) (7x^{2} – 63x) ÷ 7(x – 3)

(ii) (3p^{2} + 17p + 10 ) ÷ (p + 5)

(iii) 10xy(14y^{2} + 43y – 21) ÷ 5x(7y – 3)

(iv) 12pqr(6p^{2} – 13pq + 6q^{2}) ÷ 6pq(2p – 3q)