已知xy^2=-3,求-xy(x^3y^7-3x^2y^5-y)的值
已知xy^2=-2,求-xy(x^2y^5-xy^3-y)的值.
已知xy/x+y=2,求代数式3x-5xy+3y/-x+2xy-y的值
已知x-y=2xy,求代数式3x-5xy-3y/x+xy-y的值
已知xy=2(x+y),求(5x-xy+5y)/(3xy-x-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xy/x+y=2,求代数式3x-xy+3y/-x+3xy-y的值
已知xy/x+y=6,求3x-2xy+3y/-x+3xy-y的值.
已知3x=xy+3y,求2x+xy-2y/y-x-xy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=4xy,求x-2xy-y分之2x+3xy-2y的值!