7(a-1)+x(a-1)和3(a-b)²+6(b-a)和2(m-n)²-m(m-n)和x(x-y)²-y(y-x)²

问题描述:

7(a-1)+x(a-1)和3(a-b)²+6(b-a)和2(m-n)²-m(m-n)和x(x-y)²-y(y-x)²
m(a²+b²)-na²-nb²

7(a-1)+x(a-1)=(x+7)(a-1);3(a-b)²+6(b-a)=3(a-b)(a-b-2);2(m-n)²-m(m-n)=(m-n)(2m-2n-m)=(m-n)(m-2n);x(x-y)²-y(y-x)²=(x+y)(x-y)²;m(a²+b²)-na²-nb...