因式分解（x²-y）²-（1-y）²
问题描述：
因式分解（x²-y）²-（1-y）²
答
（x²-y）²-（1-y）²
=[(x²-y+(1-y)][(x²-y-(1-y)]
=(x²-y+1-y)(x²-y-1+y)
=(x²-2y+1)(x²-1)
=(x²-2y+1)(x+1)(x-1)