x²-2xy+y²-x+y-2=o 换成了-2
(x-y)²-(x-y)-2=0
(x-y-2)(x-y+1)=0
x-y=2 x-y=-1
x+y=8 x+y=8
∴x=5 x=7/2
y=3 y=9/2
∴S=15或63/4