每枝铅笔的售价是x元
6x+6*1.5 = 13.8
6x = 13.8 - 9
6x = 4.8
x = 0.6元加薪：4x【乘】2.5-4x=2 怎么算4x【乘】2.5-4x=210x-4x=26x=2x=1/3