解方程组x的平方+y的平方=10,x+xy+y=7

∵x^2+y^2=10,x+xy+y=7∴ 7-xy=x+y,且2xy≤x^2+y^2=10,∴(7-xy)^2=(x+y)^2=x^2+y^2+2xy=10+2xy,且xy≤5∴49-14xy+(xy)^2=10+2xy,即(xy)^2-16xy+39=0,解得xy=3或xy=13(舍去)∴x=3/y,代入x^2+y^2=10并整理得y^4-10y^2+...