Question

How do you factor `81x^4 -256`?

Answer 1

`(9x^2+16)(3x+4)(3x-4)`

Explanation:

Using the difference of two squares (`a^2-b^2=(a+b)(a-b)`) we can get:
`(9x^2+16)(9x^2-16)`

`9x^2-16=(3x+4)(3x-4)`

`(9x^2+16)(3x+4)(3x-4)`