Question

what is the method to factorise 16x4-y4

Answer 1

Take the fourth root and you will get

2x-y.

This the simplified form of the given question.

Hope it helps.

Answer 2

16x^4 - y^4
= (4x2)^2 - (y^2)^2
= (4x^2 +y^2)(4x^2 - y^2)
=(4x^2 + y^2)( (2x)^2 -y^2)
= (4x^2 + y^2)(2x + y)(2x - y).