\(B=3+3^2+3^3+3^4+...+3^{100}\)
\(B=\left(3+3^4\right)+\left(3^2+3^5\right)+...+\left(3^{97}+3^{100}\right)\)
\(B=3\left(1+3^4\right)+3^2\left(1+3^4\right)+...+3^{97}\left(1+3^4\right)\)
\(B=3.82+3^2.82+...+3^{97}.82\)
\(B=82\left(3+3^2+...+3^{97}\right)\)
\(\Rightarrow B⋮82\)
nhạt ???????????????????????????????????????