A=64+151+136+49;B=1x2x3+2x3x4+3x4x5+...+48x49x50
C=1x2x3+2x3x4+...+48x49x50
giải nhanh giúp mik vs
1x2x3+2x3x4+3x4x5+...+98x99x100
1x2x3+2x3x4+3x4x5+....+2018x2019
A=1x2x3+2x3x4+3x4x5+...+99.100.101
1x2x3+2x3x4+3x4x5+...+98x99x100
tính tổng sau :
A=1x2x3+2x3x4+3x4x5+..............+99x100x101.
2/1x2x3 + 2/2x3x4 + 2/3x4x5 + ... + 2/36x37x38 + 2/37x38x39
TÍNH TỔNG:1x2x3+2x3x4+3x4x5 + ...+ n.(n+1)(n+2)