Question

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

Answer 1

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

Explanation:

`4x^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)`.