先化简,再求值:(x^2+y^2)(x-y)+2xy(x-y),其中x=-2,y=-3
问题描述:
先化简,再求值:(x^2+y^2)(x-y)+2xy(x-y),其中x=-2,y=-3
答
(x^2+y^2)(x-y)+2xy(x-y)
=(x²+y²+2xy)(x-y)
=(x+y)²(x-y)
=(-2-3)²(-2+3)
=25