设x/2=y/3=z/4=k，故x=2k，y=3k，z=4k，所以x+2y+3z=2k+2*3k+3*4k=20k，3x+2y-2z=3*2k+2*3k-2*4k=4k，所以（x+2y+3z）/（3x+2y-2z）=20k/4k=5
