(a-b)²(a+b)² -(b-a)²(b+a)²
= (a-b)²(a+b)² -(a-b)²(a+b)²
= 0
(a-b)² -a+b
= (a-b)² -(a-b)
= (a-b)(a-b-1)
-x²(m-n)^5 -xy(n-m)^3
= xy(m-n)^3 -x²(m-n)^5
= x(m-n)^3(y-x(m-n)²)
35ab（x-y）²-25a²b²（y-x）²＋10ab³（y-x）³
= 35ab(x-y)² -25a²b²(x-y)² -10ab³ (x-y)³
= 5ab(x-y)²[7-5ab-2b²(x-y)]