1.Carry out the multiplication of the expressions in each of the following pairs:
(i) \(4p, q + r\)

(ii) \(ab, a – b\)

(iii) \(a + b, 7a^2b^2\)

(iv) \(a^2 – 9, 4a\)

(v) \(pq + qr + rp, 0\)

Multiplication of the expressions are as follows:
(i) \(4p \times (q + r) = (4p \times q) + (4p \times r) = 4pq + 4pr\)

(ii) \(ab, a – b = ab \times (a – b) = (ab \times a) – (ab \times b) = a^2b – ab^2\)

(iii) \((a + b) \times 7a^2b^2 = (a \times 7a^2b^2) + (b \times 7a^2b^2) = 7a^3b^2 + 7a^2b^3\)

(iv) \((a2 – 9) \times 4a = (a^2 \times 4a) – (9 \times 4a) = 4a^3 – 36a\)

(v) \((pq + qr + rp) \times 0 = 0\)