Question

I am trying to simplify this :
2(x-1)(x+1)^2+2(x+1)(x-1)^2

Answer 1

did you ever look at my attachment to your earlier post?

Answer 2

(x+1)(x-1)(2(x+1)+2(x-1))=(x+1)(x-1)(2(x+1+x-1)=(x+1)(x-1)(2(2x))=
=(x+1)(x-1)4x