Question

Answer 1

\(A=2+2^2+2^3+...+2^{100}\\ A=\left(2+2^2\right)+\left(2^3+2^4\right)+...+\left(2^{99}+2^{100}\right)\\ A=\left(2+2^2\right)+2^2\left(2+2^2\right)+...+2^{98}\left(2+2^2\right)\\ A=\left(2+2^2\right)\left(1+2^2+...+2^{98}\right)\\ =6.\left(1+2+...+2^{98}\right)⋮3\\ \left(đpcm\right)\)