x/3y=y/2x-5y2x^2-5xy-3y^2=0(x-3y)(2x+y)=0①x/3y=6x-15y/xx^2-18xy+45y^2=0(x-3y)(x-15y)=0②y/2x-5y=6x-15y/xxy=3(2x-5y)^2(x-3y)(12x-25)=0③若①②③同时成立,x-3y=0,x=3y(4x^2-5xy+6y^2)/(x^2-2xy+3y^2)=[4(3y...