# How do you factor -36w -wu + 9u + 4w^2?

May 24, 2015

$- 36 w - w u + 9 u + 4 {w}^{2}$

We can make groups of two to factorise this expression:
$\left(- 36 w + 9 u\right) + \left(- w u + 4 {w}^{2}\right)$

$9$ is common to both the terms in the first group, and $w$ is common to both the terms in the second group

We can write the expression as :
$9 \left(- 4 w + u\right) - w \left(- 4 w + u\right)$

=color(green)((9-w)(-4w+u)