(x-1)^2(x+1)^2(x^2+1)^2
=[(x-1)(x+1)]^2(x^2+1)^2
=(x^2-1)^2(x^2+1)^2
=[(x^2-1)(x^2+1)]^2
=(x^4-1)^2
=x^8-2x^4+1