12y(x-y)²-8(x-y)³
=4（x-y)²(3y-1)写下过程，那是8（x-y）的三次方哦，对不起，看错了，是（x-y）的三次方。12y(x-y)²-8(x-y)³=4（x-y)²(3y-2x+2y)=4(x-y)²(5y-2x)