xy-2x-2y+7=?如果xy-2x-2y+7=0则有:x(y-2)-2(y-2)+3=0(y-2)(x-2)=-3=1*-3=-1*3y-2=1,x-2=-3或y-2=-3,x-2=1,或y-2=3,x-2=-1,或y-2=-1,x-2=3分别解得:x=-1,y=3x=3,y=-1x=1,y=5x=5,y=1