已知x:y=3:5,求2y/5x的值 （比例）

已知5|x+y-3|+(x-2y)²=5,求x+y的值 已知3x-2y/x+y=5/3求x；y的值 已知x+y/3x-2y=5/3求x；y的值 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 已知5/x=3/y,求x+y/x+x-y/y-x^2-y^2/y^2的值 已知x/5=y/3,求x+y分之x+x-y分之y减y^2/x^2-y^2的值 1.已知:x-2y=3,求[(3x+2y)(3x-2y)-(x+2y)(5x-2y)]除4x 的值 已知x-2y=2011,求[(3x+2y)(3x-2y)-(x+2y)(5x-2y)]÷4x的值. 已知x-2y=2016,求[(3x+2y)(3x-2y)-(x+2y)(5x-2y)]除以8x的值 已知x-2y=2010,求[(3x+2y)(3x-2y)-(x+2y)(5x-2y)]÷8x的值 已知:x-2y=2009,求[(3x+2y)(3x-2y)-(x+2y)(5x-2y)]除以8x 的值 已知X/Y=5/3,求X/(X+Y)+X/(X-Y)-Y*2/(X*2-Y*2)的值. 已知x-y=3,求[（x+y)(x-y)-(x-y)^2+2y(x-y)]除以的值 已知x.x+y.y-6x-8y+25=0,求3x.x+5y的值 初二数学已知(x-y):y=2:3,求(2x+5y):(3x-y)的值 已知x-3y=0(y≠0)求2x+5y/3x-2y的值 已知1/x+1/y=5,求(2x-3y+2y)/(x+2xy+y)的值 已知2x-y/7x+5y=2/3且y≠0,求x/y的值