x:y:z=2:3:4
所以y=3x/2,z=2x
所以(x+2y)/y
=(x+3x)/(3x/2)
=4/(3/2)
=8/3
(x+2y+3z)/(3x-2y-z)
=(x+3x+6x)/(3x-3x-3x)
=10/(-3)
=-10/3