# How do you factor completely 4y^2-36?

$4 \left(y - 3\right) \left(y + 3\right)$
$4 {y}^{2} - 36$
= $4 \left({y}^{2} - 9\right)$
= $4 \left(y - 3\right) \left(y + 3\right)$