# Question #bdde3

Jan 28, 2018

See below...you'll get it in under a minute...

#### Explanation:

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

You just have to use the identity:
$\left({a}^{2} - {b}^{2}\right) = \left(a + b\right) \left(a - b\right)$