x^2-xy+y^2=3,2x^2-xy-y^2=55x^2-5xy+5y^2=156x^2-3xy-3y^2=15两式子相减x^2+2xy-8y^2=0(x+4y)(x-2y)=0x=2y或者x=-4y当x=2y时代入第一个式子有4y^2-2y^2+y^2=33y^2=3y=±1此时x=2,y=1或者x=-2,y=-1如果x=-4y代入式子...