4x=9y,求x+y/y;y-x/2x请给我完整过程

4x=9y,求x+y/y;y-x/2x请给我完整过程 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 如果|X|=4 |Y|=2 且|X+Y|=X+Y 求X+Y 已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值 2x-y=2,求[(x²+y²)-(x-y)²+2y(x-y)]÷4y 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 已知2y-x=-3,求[4y(2x-y)-2x(2x-y)]/(2x-y 已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y² 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 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 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3(x+y)-2(x-y)=11 4(x+y)+3(x-y)=9 已知:【(x²+y²)-(x-y)²+2y(x-y)】/4y=1,求4x/4x²-y²-1/2x+y 已知x-y=1,求[(x+2y)^2+(2x+y)(x-4y)-3(x+y)(x-y)]除以y的值大神们帮帮忙 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值 已知4x=9y求(1)x+y/y (2)y-x/2x有关比例的 已知,X:Y=3:2,求代数式4X-9Y:2X+3Y 已知x/y=3/2求代数式4x-9y/2x+3y