Question

Carry out the multiplication of expressions in each of the following pairs.
(i) $4p,q+r$
(ii) $ab,a-b$
(iii) $a+b,7a^2{b}^2$
(iv) $(a^2-9)\times \left(4a\right)$
(v) $pq+qr+rp,0$

Answer 1

(i) $\left(4p\right)\times (q+r)$
$=(4p\times q)+(4p\times r)$

$=4pq+4pr$

(ii) $ab\times (a-b)$
$=(ab\times a)+(ab\times (-b\left)\right)$

$=a^2{b}^2-a{b}^2$

(iii) $(a+b)\times \left(7a^2{b}^2\right)$
$=(a\times 7a^2{b}^2)+(b\times 7a^2{b}^2)$

$=7a^3{b}^2+7a^2{b}^3$

(iv) $(a^2\times 4a)+(-9\times 4a)$

$=4a^3-36a$

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

$=0+0+0$

$=0$