已知xy+x=2003,y+xy=2002,则—(y—x)=

|x|/x+y/|y|+xy/|xy|= 已知xy+x=2003,y+xy=2002,则—(y—x)= 已知x+y=1,xy=-2,则x²y+xy²-2xy 已知x-xy=8,xy-y=-9,求x+y-2xy的值 已知xy>0,证明xy+xy/1+x/y+y/x>=4 由已知x+y=-2,xy=3那么2(x+xy)-[(xy-3y)-x]-(-xy)等于多少? 已知xy^2=-2,求-xy（x^2y^5-xy^3-y)的值. 已知xy^2=-2 求-xy(x^2y^5-xy^3-y) 已知xy^2=-2xy(x^2y^5-xy^3-y) 已知x+y=12,xy=9,求(x+3xy+y)/(xy+xy)的值 已知x^2-xy=5,xy-y^2=-3求3(x^2-xy)-xy+y^2 已知x^-xy=5,xy-y^=-3,求式子3(x^-xy)-xy+y^的值 已知x:y=3:2,求(x²+3xy)/(xy+2xy) 已知x+y=4,xy=3,则-xy-xy= 3xy+xy+3+4xy-7化简,已知x=5,y=6 已知xy为正整数,3xy=2x+3y+5.求xy=? 已知xy+xy=13,xy+yx=120,求x,y 已知XY为正数,X+Y=1 求1/XY+XY的最小值