(5x-4y)(3x-7y)=0 且xy≠0 求x/y的值

已知xy≠0,且2x+3xy-2y=0,求(x+y)/(x-y)的值. 已知x-y=4xy且xy≠0,求代数式-x-2xy+y分之2x+3xy-2y的值 已知x-7y=0,且y≠0,求2x²﹢xy-3y²分之x²-3xy+y²的值 已知5x-4y=0且xy不等于0,求x^2+y^2/x^2-y^2-x+y/x-y的值 已知3x^2-xy-4y^2=0,且x≠y求x-2y/x+2y的值 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 已知x^2-xy+3y^2=0 且xy不等于0 求x/y+y/x 的值 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 (1)已知x-y=6,xy=4,求xy^-1+x^-1y的值； (2)已知x^2+y^2=3xy且xy≠0,求x^2y^ 已知x^2+3xy-4y^2=0(y≠0),求x-y/x+y的值. x>1,y>0,且满足xy=x^y,x/y=x^3y,求x+y 若x＞0,y＞0,且√x(√x+√y)=3√y（√x+5√y）,求（2x+2√xy+3y）/（x-√xy+y）的值.