已知x^+xy=-5,xy+y^=8,求2x^-xy-3y^的值

已知xy^2=-2,求-xy（x^2y^5-xy^3-y)的值. 已知x-xy=8,xy-y=-9,求x+y-2xy的值 已知xy/x+y=2,求代数式3x-5xy+3y/-x+2xy-y的值 已知xy=2(x+y),求(5x-xy+5y)/(3xy-x-y)的值 已知x-y=2xy,求代数式3x-5xy-3y/x+xy-y的值 已知x^-xy=5,xy-y^=-3,求式子3(x^-xy)-xy+y^的值 已知,xy/x+y=3,求代数式3x-5xy+3y/-x+3xy-y的值 已知xy/x+y=3,求代数式3x-5xy+3y/-x+3xy-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/xy=3,求分式2x+3xy-2y/x-2xy-y的值. 已知3x=xy+3y,求2x+xy-2y/y-x-xy的值