已知x y满足等式2x+x²+x²y²+2=-2xy,x+y值为 A.-1 B.0 C.2 D.1
问题描述:
已知x y满足等式2x+x²+x²y²+2=-2xy,x+y值为 A.-1 B.0 C.2 D.1
答
2x+x²+x²y²+2=-2xy
2x+x²+x²y²+2+2xy=0
(x+1)^2 +(xy+1)^2 =0
x=-1,xy=-1,y=1
x+y=0
B