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) $$pq + qr + rp, 0$$

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