Question

tinh m =2*3*4+3*4*5+...+2018*2019*2020

Answer 1

\(M=2.3.4.4+3.4.5.4+...+2018.2019.2020.4\)

\(M=2.3.4.\left(5-1\right)+3.4.5.\left(6-2\right)+...+2018.2019.2020.\left(2021-2017\right)\)

M=2.3.4.5-1.2.3.4+3.4.5.6-2.3.4.5+...+2018.2019.2020.2021-2017.2018.2019.2020=2018.2019.2020-1.2.3.4

Answer 2

ok biết lm tiếp r

Answer 3

nhưng phải chia 4 nữa