解答如下:设x = 2k,y = 3k,z = 4k代入得原式 = (4k - 3k + 16k)/(9k)= 17/9
假设x/2=y/3=z/4=1,那么x=1,y=6,z=4.则(2x-y+4z)/3y=(2*2-3+4*4)/3*3=17/9
17/9