Question

[đào thu uyên]

giúp e với e camon

Answer 1

[Hồng Nhan]

Bài 5:

\(5^{n+2}+26.5^n+8^{2n+1}\)

\(=25.5^n+26.5^n+8.64^n\)

\(=51.5^n+8.64^n\)

\(=51.5^n+8.5^n+8.64^n-8.5^n\)

\(=59.5^n+8\left(64^n-5^n\right)\)

Ta thấy: \(\left\{{}\begin{matrix}59.5^n⋮59\\8\left(64^n-5^n\right)⋮\left(64-5\right)=59\end{matrix}\right.\)

⇒ \(59.5^n+8\left(64^n-5^n\right)⋮59\)

⇒ \(5^{n+2}+26.5^n+8^{2n+1}\)  ⋮ \(59\)

⇒ \(ĐPCM\)

Answer 2

[Hồng Nhan]