x-3y=2 2x+y=18 求xy

若1/x-1/y=2,求3x-2xy-3y/x-xy-y的值3x-2xy-3y/x-xy-y 不好意思，是3x-2xy-3y/x-2xy-y 当x-y=2xy时,求4x-3xy-4y/xy 已知xy=-2,x-y=3,求（x+y)（x-y)-y^2+（x-y)^2-（6x^2y-2xy^2)÷2y 已知X+Y=3XY,求2X+2Y-XY除以X+Y+2XY的值,要算理.已知X+Y=3XY,求2X+2Y-XY除以X+Y+2XY的值,要算理. 已知y=3xy+x,求代数式2x+3xy-2y/x-2xy-y的值 若(y-x)/xy=3,求分式(2x+3xy-2y)/(x-2xy-y)的值 若y-x/xy=3,求分式2x+3xy-2y/x-2xy-y 已知x-y/xy=3,求分式2x+3xy-2y/x-2xy-y的值. 已知3/(x-y)=1/xy 求(-x-2xy+y)/ (2x+3xy-2y) 已知x-y=3xy,求2x+3xy-2y/x-2xy-y 已知x-y=3xy,求2x-3xy-2y/x-2xy-y 已知y=3xy+x,求代数式2x+3xy-2y/x-2xy-y的值 x-y+3xy=0 求2x+3xy-2y/x-2xy-y的值 已知xy/x+y=3,求2x-3xy+2y/-x+3xy-y的值 xy/x+y=3求2x-3xy+2y/3xy-x-y的值 已知xy/x+y=3,求2x-3xy+2y/-x+3xy-y的值 已知x-y=3xy,求分式3x+2xy-3y/x-2xy-y的值 已知x+y=3xy,求2x+2y-xy/x+y+2xy的值、