3x-4y-6z=14 (1)
2x-8y +2z=15 (2)
3x+4y+6z=16 (3)
(1)+(3),
6x=30
x=5
代入(1),(2)
15-4y-6z=14 (4)
10-8y +2z=15 (5)
(4)×2-(5),
20-14y=13
z=1/2
x=5,z=1/2代入(1),
15-4y-3=14
y=-1/2
x=5,y=-1/2,z=1/2