1. a) \(4< 2^n< 2.16\)
\(\Rightarrow\) \(4< 2^n< 32\)
\(\Rightarrow2^2< 2^n< 2^5\)
\(\Rightarrow\left\{{}\begin{matrix}x=3\\x=4\end{matrix}\right.\)
b) \(\left(x-\dfrac{2}{7}\right).3=\dfrac{2}{3}.6\)
\(\Rightarrow\left(x-\dfrac{2}{7}\right).3=4\)
\(\Rightarrow x-\dfrac{2}{7}=\dfrac{4}{3}\)
\(\Rightarrow x=\dfrac{34}{31}\)
a) \(4< 2^n< 2.16\)
\(\Leftrightarrow4< 2^n< 32\)
\(\Rightarrow2^2< 2^n< 2^5\)
\(\Rightarrow n\in\left\{3;4\right\}\).
b) \(\left(x-\dfrac{2}{y}\right).3=\dfrac{2}{3}.6\)
\(\Leftrightarrow\left(x-\dfrac{2}{7}\right).3=\dfrac{12}{3}\)
\(\)\(\Leftrightarrow x-\dfrac{2}{7}=\dfrac{12}{3}:3\)
\(\Leftrightarrow x-\dfrac{2}{7}=12\)
\(\Leftrightarrow x=12+\dfrac{2}{7}\)
\(\Rightarrow x=\dfrac{86}{7}\).
