5x^2+7xy+6y^2=0求x/y

已知x>0,y>0,且x+6y=5根号xy,求(2x+根号xy-y)分之(x+根号xy+2y)的值 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值 5x^2+7xy+6y^2=0求x/y 已知X-XY-2Y=0求2X+3XY-Y/X-2XY+5Y 若x+y-5xy=0,求(2x-3xy+2y)/(x+2xy+y)的值 诺x+y=6,xy=4 求(5x-4y-3xy)-(8x-y+2xy) 求（3x^+y^-5xy）-【2x^-（-4xy-y^+7x^）】=? 求（3x^+y^-5xy）-【2x^-（-4xy-y^+7x^）】=? x+y=8,xy=-2,求(5xy+4x+7y)+(6x-3xy)-(4xy-3y)的值 已知X+y=6,xy=7 求x^2y+xy^2=已知X+y=6,xy=7 x^2y+xy^2 已知x^2+y^2-4x+6y+13=0求(xy+y^2/5x^2-5xy+xy+y^2)·（5/x+y）-（y/x-y） 已知xy^2=-6,求-xy(x^3y^7-3x^2y^5-y）的值 已知x>0,y>0,x+根号xy-6y=0,求4x+5根号xy-6y分之x+2根号xy 已知x+y=2xy,且xy不等于0,则求-2x+6xy-2y/(7x+5y)-9xy-(3x+y)=___ 已知x^2-6xy+9y^2=0,求(x-y)/(x+y) 已知x,y>0 2x+y+3=xy 求5x+4y最小值 已知x^2+9y^2-2x-6y+2=0,求{-（xy/（x-y）^2}^4*(y^2-xy/x)^3*x^4/y^10/(x/xy-y^2)^5的值 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值?