题目

x+y=3,xy=-2,求x(x+y)(x-y)-x{(x+y)的2次方} (≥▽≤)/~

提问时间：2020-12-20

答案

原式=-2xy(x+y)
=-2(-2)*3
=12
(原式=x(x+y)[x-y-(x+y)]
=x(x+y)(-2y)
=-2xy(x+y) )