Question

Multiply.

(i) $16xy\times 18xy$ (ii)$23x{y}^2\times 4y{z}^2$

(iii) $(12a+17b)\times 4c$ (iv) $(4x+5y)\times (9x+7y)$

Answer 1

(i) $16xy\times 18xy$
$=$ $16\times 18\times x\times y\times x\times y$
$=288x^2{y}^2$
(ii) $23x{y}^2\times 4y{z}^2$
$=$ $23\times 4\times x\times y^2\times y\times z^2$

$=$ $92x{y}^3{z}^2$
(iii) $(12a+17b)\times 4c$
$=$ $12a\times 4c+17b\times 4c$
$=$ $12\times 4\times a\times c+17\times 4\times b\times c$
$=$ $48ac+68bc$
(iv) $(4x+5y)\times (9x+7y)$
$=$ $4x(9x+7y)+5y(9x+7y)$
$=$ $4x\times 9x+4x\times 7y+5y\times 9x+5y\times 7y$
$=$ $36x^2+28xy+45xy+35y^2$
$=$ $36x^2+73xy+35y^2$