đặt \(A=2+2^2+2^3+...+2^{2018}\)
\(\Rightarrow2A=2^2+2^3+2^4+...+2^{2019}\)
\(\Rightarrow2A-A=2^{2019}-2\)
\(\Rightarrow A=2^{2019}-2\)
(2^2019-2)/2 1. hiện tại không thể trả lời
\(\frac{25^2\cdot25^3}{5^{10}}\)
\(=\frac{25^{2+3}}{5^{10}}\)
\(=\frac{25^5}{5^{10}}\)
\(=\frac{\left(5^2\right)^5}{5^{10}}\)
\(=\frac{5^{10}}{5^{10}}=1\)
\(\frac{25^2\cdot25^3}{5^{10}}=\frac{\left(5^2\right)^2\cdot\left(5^2\right)^3}{5^{10}}=\frac{5^4\cdot5^6}{5^{10}}=1\)