a) \(2.16 \ge {2^n} > 4 \)
\(\Rightarrow {2.2^4} \ge {2^n} > {2^2}\)
\( \Rightarrow {2^5} \ge {2^n} > {2^2} \)
\(\Rightarrow 2 < n \le 5\)
\(\Rightarrow n \in \left\{ {3;4;5} \right\}\)
b) \(9.27 \le {3^n} \le 243\)
\(\Rightarrow {3^2}{.3^3} \le {3^n} \le {3^5}\)
\( \Rightarrow {3^5} \le {3^n} \le {3^5}\)
\(\Rightarrow n = 5\)
