Đáp án:
`A=2^2016`
Giải thích các bước giải:
`A=8+2^3+2^4+2^5+...+2^2015`
$\Rightarrow A=8+\underbrace{2^3+2^4+2^5\,+\,.\!.\!.+\,2^{2015}}_{\large A'}\\\Rightarrow A'=2^3+2^4+2^5\,+\,.\!.\!.+\,2^{2015}\\\Rightarrow 2A'=2.(2^3+2^4+2^5\,+\,.\!.\!.+\,2^{2015})\\=2A'=2^4+2^5+2^6\,+\,.\!.\!.+\,2^{2016}\\\Rightarrow 2A'-A'=(2^4+2^5+2^6\,+\,.\!.\!.+\,2^{2016})-(2^3+2^4+2^5\,+\,.\!.\!.+\,2^{2015})\\\Rightarrow A'=2^{2016}-2^3\\\Rightarrow A=8+2^{2016}-2^3\\\Rightarrow A=2^3+2^{2016}-2^3\\\Rightarrow A=2^{2016}$
Vậy `A=2^2016`.
