一道减算题（2＋0.75×1）+（2＋0.75×2

一道减算题（2＋0.75×1）+（2＋0.75×2）+（2＋0.75×3）+…+（2＋0.75×11）得多少?

3个回答

（2＋0.75×1）+（2＋0.75×2）+（2＋0.75×3）+…+（2＋0.75×11）
=2*11+0.75*(1+2+3+4……11)
=22+0.75*66
=22+49.5
=71.5