3又1/8/[(17.2-3.6x)/0.32]=1
3又1/8＝[(17.2-3.6x)/0.32]
25/8＝(17.2-3.6x)/0.32
25＝(17.2-3.6x)/0.04
1＝17.2-3.6x
3.6x=16.2
x=4.5