3x-y+z=4 (1)
2x+3y-z=12 (2)
x+y+z=6 (3)
(1)+(2)
5x+2y=16 (4)
(2)+(3)
3x+4y=18 (5)
(4)×2-(5)
10x-3x=32-18
所以
x=2
y=(18-3x)/4=3
z=4-3x+y=1
3x-y+z=4 (1)
2x+3y-z=12 (2)
x+y+z=6 (3)
(1)+(2)
5x+2y=16 (4)
(2)+(3)
3x+4y=18 (5)
(4)×2-(5)
10x-3x=32-18
所以
x=2
y=(18-3x)/4=3
z=4-3x+y=1