x方y方-x方-y方+1因式分解
问题描述：
x方y方-x方-y方+1因式分解
答
x方y方-x方-y方+1
=x²(y²-1)-(y²-1)
=(y²-1)(x²-1)
=(x+1)(x-1)(y+1)(y-1)