已知7x+5y/2y-x=3/2,且x≠0,求X/x-4y

已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 已知3x-2y-5z=0,2x-5y+4z=0,且x,y,z均不为0,求3x*x+2y*y+5z*z/5x*x+y*y- 已知X、Y满足2X-7Y=3M,X+2Y=4m+5,且X+Y=0,求M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-2y-5z=0,2x-5y+4z=0,且x,y,z都不为0,求（3x*x+y*y+4z*z）/（5x*x+y* 已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-( 已知4x-3y-6z=0,x+2y-7z=0,且x,y,z≠0,求2x+3y+6z/x+5y+5z的值. 已知x,y>0 2x+y+3=xy 求5x+4y最小值 已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y 已知3x^2-xy-4y^2=0,且x≠y求x-2y/x+2y的值 已知x,y满足2x-7y=3m,x+2y=4m+5,且x+y=o,求m的值 已知x.y满足2x-y=3m,x+2y=4m+5,且x+y=0,求m的值