y+2z=-2 (1)
3x-4z=1 (2)
2x-y=8 (3)
(1)+(3)
2x+2z=6
所以4x+4z=12 (4)
(2)+(4)
7x=13
x=13/7
y=2x-8=-30/7
z=(-y-2)/2=8/7