计算：合并同类项2（x-y）²-3（x-y）³-（x-y）²+2（x-y）³-6（y-x）²原式=

计算：合并同类项
2（x-y）²-3（x-y）³-（x-y）²+2（x-y）³-6（y-x）²
原式=

解
原式
=2(x-y)²-3(x-y)³-(x-y)²+2(x-y)³-6(x-y)²
=(2-1-6)(x-y)²+(2-3)(x-y)³
=-5(x-y)²-(x-y)³

原式=2(x-y)^2-6(x-y)^2-(x-y)^2+2(x-y)^3-3(x-y)^3=-5(x-y)^2-(x-y)^3=(x-y)^2(5-x+y)