Question

已知x,y满足等式2x+x²+x²y²+2=2xy,哪么x+y的值为

Answer 1

2x+x^2+x^2y^2+2=-2xy

x^2+2x+1+x^2y^2+2xy+1=0

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

x+1=0 xy+1=0

x=-1 y=1

x+y=0