2x-y+3z=3(1)
3x+y-2z=-1(2)
x+y+z=5(3)
(1)+(2)
5x+z=2(4)
(1)+(3)
3x+4z=8(5)
(4)*4-(5)
17x=0
x=0
代入（4）z=2
y=3
解得x=0,y=3,z=2