# How do you factor  25z^2 - 36b^2?

Mar 20, 2016

 =color(blue)((5z + 6b) (5z - 6b)

#### Explanation:

$25 {z}^{2} - 36 {b}^{2}$

The expression can also be written as:
${\left(5 z\right)}^{2} - {\left(6 b\right)}^{2}$

This is of the form :
color(blue)(a^2 - b ^2 = (a+b)(a-b)

(5 z) ^2 - (6b)^2 = color(blue)((5z + 6b) (5z - 6b)

The factorised form of the expression is:
color(blue)((5z + 6b) (5z - 6b)