由已知x+y=-2,xy=3那么2(x+xy)-[(xy-3y)-x]-(-xy)等于多少?

分类: 作业答案 • 2022-09-24 21:08:26

问题描述：

答

2(x+xy)-[(xy-3y)-x]-(-xy)
=2x+2xy-xy+3y+x+xy
=3x+3y+2xy
=3（x+y）+2xy
=3*（-2）+2*3
=0