4x-y+3z=0 (1)
2x+y+6z=0 (2)
()+(2)
6x+9z=0
6x=-9z
z/x=-2/3
(1)*2-(2)
8x-2y-2x-y=0
6x-3y=0
6x=3y
x/y=1/2
z/x=-2/3
x/y=1/2
相乘,z/y=-1/3
y/z=-3
x/y+y/z+z/x
=1/2-3-2/3
=-19/6