=2+7=9x等于多少，y等于多少（要过程x^2+xy=2 =>x(x+y)=2xy++y^2=7 =>y(x+y)=7上面两式相加即可得出x^2+2xy+y^2=9。=>x+y=-3或者3代回上面任意一个式子=>x=2/3 y=7/3或者x=-2/3, y=-7/3谢啦