2(x-y)-3(y-x)的两次方
=2(x-y)-3(x-y)的两次方
=(x-y)*[2-3(x-y)]
=(x-y)*[2-3x+3y]
＝（x-y）*[2-3(x+y)}]yt谢谢
希望可以帮到你哦