将(x-y)看成一个整体,将3(x-y)²-4(x-y)+7(x-y)-6(y-x)²-2(y-x)合并同类项.

问题描述:

将(x-y)看成一个整体,将3(x-y)²-4(x-y)+7(x-y)-6(y-x)²-2(y-x)合并同类项.

3(x-y)²-4(x-y)+7(x-y)-6(y-x)²-2(y-x)=-3(x-y)²+5(x-y)