4x-3y-6z=0,x+2y-7z=0,x-y+z/x+y+z=?

4x-3y-6z=0,x+2y-7z=0,x-y+z/x+y+z=?
4x-3y-6z=0,x+2y-7z=0,x-y+z/x+y+z=?

4x-3y-6z=0,x+2y-7z=0,x-y+z/x+y+z=?
解方程组
4x-3y-6z=0
x+2y-7z=0
得：
x=3z,y=2z
x-y+z/x+y+z
=(3z-2z+z)/(3z+2z+z)
=2z/6z
=1/3

4x-3y=6z
x+2y=7z
解出方程组：
x=3z
y=2z
代入后面的算式得：
3z-2z+z/3z+2z+z=2z/6z=1/3