Question

Carry out the multiplication of the expressions in each of the following pairs.

(i) 4p, q + r (ii) ab, a − b (iii) a + b, 7a2b2

(iv) a2 − 9, 4a (v) pq + qr + rp,

Answer 1

(i) (4p) × (q + r) = (4p × q) + (4p × r) = 4pq + 4pr

(ii) (ab) × (a − b) = (ab × a) + [ab × (− b)] = a2b − ab2

(iii) (a + b) × (7a2 b2) = (a × 7a2b2) + (b × 7a2b2) = 7a3b2 + 7a2b3

(iv) (a2 − 9) × (4a) = (a2 × 4a) + (− 9) × (4a) = 4a3 − 36a

(v) (pq + qr + rp) × 0 = (pq × 0) + (qr × 0) + (rp × 0) = 0