已知xy满足等式x^2+2x+x^2y^2+2xy+2=0那么x+y的值是

问题描述:

已知xy满足等式x^2+2x+x^2y^2+2xy+2=0那么x+y的值是

(x+1)^2+(xy+1)^2=0
xy=-1
x=-1
y=1
x+y=0