# How do you factor 4x^4 - y^2?

Jul 3, 2015

4x^4 - y^2 =color(blue)((2x^2+y)(2x^2-y)

#### Explanation:

$4 {x}^{4} - {y}^{2}$ is of the form color(blue)(a^2 - b^2 (where a=2x^2 , b=y) , and as per the identity:
color(blue)(a^2 - b^2= (a+b)(a-b)

So, 4x^4 - y^2 =color(blue)((2x^2+y)(2x^2-y).