已知x-2y=-2,xy=8,求x^3y-4x^2y^2+4xy^3,求值.

已知xy/x+y=2,求代数式8x-5xy+8y/-x+3xy-y的值 已知x-xy=8,xy-y=-9,求x+y-2xy的值 已知1/x+1/y=8,求2x-3xy+2y/x+2xy+y的值 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:x/y=-2,求x^2-2xy-3y^2/x^-6xy 已知x,y为正整数,并且xy+x+y=71,x^2y+xy^2=880,求3x²+8xy+3y² 已知xy=-2,x-y=3,求（x+y)（x-y)-y^2+（x-y)^2-（6x^2y-2xy^2)÷2y 已知y=3xy+x,求代数式2x+3xy-2y/x-2xy-y的值 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 已知xy/x+y=3,求2x-3xy+2y/-x+3xy-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、 已知x-y=4xy,求2x+3xy-2y/x-2xy-y的值