x^2+xy+y^2=4=>2x^2+2xy+2y^2=8联立3x^2-y^2=8相减得=>x^2-2xy-3y^2=0=>(x-3y)(x+y)=0=>x=3y或x=-y讨论：1)x=3y=>3(3y)^2-y^2=8=>26y^2=8=>y=正负（根号（4/13））x=正负3*（根号（4/13））2)x=-y=>(-y)^2+(-y)*y+y^...