求:3*(1*2+2*3+3*4+...+99*100)=?

2025-03-03 17:47:13
推荐回答(1个)
回答1:

3*(1x2+2x3+3x4+...+99x100)
=3*1/3*(1x2x3-0x1x2+2x3x4-1x2x3+3x4x5-2x3x4+99x100x101-98x99x100)
=99x100x101