6x^2-5xy+y^2=0 （1）x^2+xy+y^2=7 （2）由（1）得:(3x-y)(2x-y)=0,3x-y=0,2x-y=0y=3x(3)或y=2x(4)把(3)(4)分别代入（2）得:x^2+3x^2+9x^2=7,13x^3=7,x=±7√91x^2+2x^2+4x^2=7,7x^2=7,x=±1分别代入(3)(4)得方程组...