题目内容：

分解因式；
1、m(x-y)²-x+y
2、（a-b)²-3a+3b
3、x²(x+y)(y-x)-xy(x+y)(x-y)
4、已知a+b=2,ab=-1/2,求a(a+b)(a-b)-a(a+b)²

优质解答

(mx+my)(x-y)-(x-y)
(mx+my-1)(x-y)
(a-b)(a-b)-3(a-b)
=(a-b-3)(a-b)
x^2(x+y)(y-x)+xy(x+y)(y-x)
=(x^2+xy)(x+y)(y-x)
=x(x+y)^2(y-x)
a(a+b)(a-b-a-b)
=-2ab(a+b)
=2