# How do you factor completely 6y^2 - 54?

$6 \left(y - 3\right) \left(y + 3\right)$
$6 {y}^{2} - 54 = 6 {y}^{2} - 6 \cdot 9 = 6 \left({y}^{2} - 9\right) = 6 \left[{\left(y\right)}^{2} - {\left(3\right)}^{2}\right] = 6 \left(y - 3\right) \left(y + 3\right)$