Question

Answer 1

c, \(=16.5-[131-81]=80-50=30\)

d, Ta có:

\(A=4+4^2+4^3+4^4+...+4^{2020}+4^{2021}\)

\(\Rightarrow4A=4^2+4^3+4^4+...+4^{2021}+4^{2022}\)

\(\Rightarrow4A-A=\left(4^2+4^3+4^4+...+4^{2021}+4^{2022}\right)-\left(4+4^2+4^3+4^4+...+4^{2020}+2021\right)\)

\(\Rightarrow A=4^{2022}-2\)