x=y-z=y-8+y=2y-8
z=8-y
代入3式
100x+10y+z+99=100z+10y+x
99x+99-99z=0
x-z+1=0
2y-8-8+y-1=0
y=17/2
z=-1/2
x=9好像错了，不信你把这些代入3式看看2y-8-8+y+1=0
y=5
z=3
x=2
呵呵~~