提取公因式法
问题描述：
提取公因式法
1.(x-2)^-x+2
2.x^2y(x-y)-xy^2(y-x)
答
1.(x-2)²-x+2
=（x-2)²-(x-2)
=(x-2)(x-2-1)
=(x-2)(x-3)
2.x²y(x-y)-xy²(y-x)
=x²y(x-y)+xy²(x-y)
=xy(x-y)(x+y)