Question

Factorise the following expression
$20l^{2}m+30alm$

Answer 1

$20l^{2}m=2\times 2\times 5\times l\times l\times m$

$30alm=2\times 3\times 5\times a\times l\times m$

The common factors are $2,5,landm$

$\therefore 20l^{2}m+30alm$

$=(2\times 2\times 5\times l\times l\times m)+(2\times 3\times 5\times a\times l\times m)$

$=(2\times 5\times l\times m)\left[\right(2\times l)+(3\times a\left)\right]$ [Taking $2,5,l,m$ as common]

$=10lm(2l+3a)$