(y-x)的二次方(x-y)+(x-y)的三次方+2(x-y)的二次方(y-x)在线等,秒回
问题描述：
(y-x)的二次方(x-y)+(x-y)的三次方+2(x-y)的二次方(y-x)在线等,秒回
答案已有,求大神讲解
答
(y-x)²(x-y)+(x-y)³+2(x-y)²(y-x)
=(x-y)²(x-y)+(x-y)³-2(x-y)²(x-y)
=(x-y)³+(x-y)³-2(x-y)³
=2(x-y)³-2(x-y)³
=0-2(x-y)²(x-y)为什么会变成-号，如何转换的2(x-y)²(y-x)=2(x-y)²[-(x-y)]=-2(x-y)²(x-y)把-号提到前面就行。