XY+X+Y-7=0
xy+x+y+1=8
(x+1)(y+1)=8=1*8=2*4=-1*(-8)=-2*(-4)
x+1=1,y+1=8,得：x=0,y=7
x+1=8,y+1=8,得：x=7,y=0
x+1=2,y+1=4,得：x=1,y=3
x+1=4,y+1=2,得：x=3,y=1
x+1=-1,y+1=-8,得：x=-2,y=-9
x+1=-8,y+1=-1,得：x=-9,y=-2
x+1=-2,y+1=-4,得：x=-3,y=-5
x+1=-4,y+1=-2,得：x=-5,y=-3