假设铅笔A元和圆珠笔B元小红买3支铅笔和2支圆珠笔共用3.93A+2B=3.9小林买2支铅笔和3支圆珠笔花了4,6元2A+3B=4.6(3A+2B)+(2A+3B)=3.9+4.65A+5B=8.5A+B=1.7A=(3A+2B)-2*(A+B)A=3.9-3.4A=0.5B=(2A+3B)-2*(A+B)B=4.6-3.4B=1.2