已知4x-3y-6z=0,x+2y-7z=0(x,y,z均不为0) ,求(2x+3y+6z)/(x+5y+5z)的值

已知4x-3y-6z=0,x+2y-7z=0(x,y,z均不为0) ,求(2x+3y+6z)/(x+5y+5z)的值
已知4x-3y-6z=0,x+2y-7z=0(x,y,z均不为0) ,求(2x+3y+6z)/(x+5y+5z)的值

已知4x-3y-6z=0,x+2y-7z=0(x,y,z均不为0) ,求(2x+3y+6z)/(x+5y+5z)的值
4x-3y-6z=0...(1)
x+2y-7z=0...(2)
(2)*4-(1):
11y=22z
y=2z
代入（2）：x+4z-7z=0
x=3z
将y=2z,x=3z代入(2x+3y+6z)/(x+5y+5z)
=（6z+6z+6z)/(3z+10z+5z)
=18z/18z
=1