①a（a-b）+b（b-a）=(a-b)(a-b)=(a-b)²②（a-b）³-（a-b）² =(a-b)²(a-b-1)③x（x+y）（x-y）-x（x+y）²=(x+y)x(x-y-x-y)=-2xy(x+y)④2a（x-y）-4b（y-x）=2(x-y)(a+2b)⑤（2x+y）（2x-3y...