已知x-xy=20,xy-y=-10,则x-y=?,x+y-2xy?
已知x-y=4xy,则2x+3xy-2yx-2xy-y
已知:x-xy=40,xy-y=-20,求代数式x-y和x+y-2xy的值.
已知xy/x+y=1/2,则代数式3x-5xy+3y/-x+3xy-y=
已知x-xy=8,xy-y=-9,求x+y-2xy的值
由已知x+y=-2,xy=3那么2(x+xy)-[(xy-3y)-x]-(-xy)等于多少?
已知:xy+x=-1,xy-y=-2.
已知x+y=5,xy=2则x^2y+xy^2=( )
已知x+y=1,xy=1/5,则x^2y=xy^2
已知x+y=6,xy=-3,则x^2y+xy^2=?
已知x+y=6,xy=-3,则x^2y+xy^2=
已知x+y=5,xy=-3,则x^2y+xy^2,
已知xy/x+y=2,则代数式3x-5y+8y/-x+3xy-y的值