y+2z=-2 (1)
3x-4z=1 (2)
2x-y+2z=8 (3)
(1)*2+(2)得
3x+2y=-3 (4)
(3)-(1)得
2x-2y=10 (5)
(4)+(5)得
5x=7
x=7/5
把x代入(2)、(4)得
y=-18/5
z=4/5