Question

S= 1+2+2²+2³+...........+2⁴⁹+ 2018 ko chia hết cho3

Answer 1

S= 1+2+2²+ 2³+..............+ 2⁴⁹ +2018

Answer 2

\(S=\left(1+2\right)+2^2\left(1+2\right)+...+2^{48}\left(1+2\right)+2018\)

\(=3\left(1+2^2+...+2^{48}\right)+2018\)

Vì 2018 ko chia hết cho 3

nên S ko chia hết cho 3