mk chắc chắn 100% là n >1
b)\(27< 3^n< 243\)
\(3^3< 3^n< 3^5\)
\(\Rightarrow3< n< 5\)
\(\Rightarrow n\in\left\{4\right\}\)
a)\(\frac{1}{8}.16^n=2^n\)
\(\frac{16^n}{8}=2^n\)
\(\Rightarrow\frac{2^{4n}}{2^3}=2^n\)
\(\Rightarrow2^{4n-3}=2^n\)
\(\Rightarrow4n-3=n\)
\(\Rightarrow n=1\)