
\begin{enumerate}
\item
\begin{enumerate}
\item $x^2=10 \iff x=-\sqrt{10}\text{ ou }x=\sqrt{10}$

$$\boxed{ S=\left\{-\sqrt{10};\sqrt{10}\right\} }$$

\item $x^3=216 \iff x=\sqrt[3]{216} \iff x = 6$.
$$\boxed{S = \{6\} }$$

\item $\sqrt{x}=8 \iff x = 8^2 \iff x = 64$.

$$\boxed{S = \{64\} }$$

\item $\dfrac{1}{x}=5 \iff x = \dfrac{1}{5}$.

$$\boxed{S = \left\{\dfrac{1}{5}\right\}}$$
\end{enumerate}

\item
\begin{enumerate}
\item $x^2<6 \iff -\sqrt6 < x < \sqrt6 \iff \boxed{x\in\intervOO{-\sqrt6}{\sqrt6}}$.

\medskip

\item $x^2\geqslant10 \iff x\leqslant\sqrt{10}\text{ ou }x\geqslant\sqrt{10}\iff \boxed{x\in\intervOF{-\infty}{\sqrt{10}}\cup\intervFO{\sqrt{10}}{+\infty}}$.

\medskip

\item $x^3<8 \iff x < \sqrt[3]{8} \iff x < 2 \iff \boxed{x\in\intervOO{-\infty}{2}}$.

\medskip

\item $\sqrt{x}\leqslant4 \iff 0 \leqslant x \leqslant 4^2 \iff 0\leqslant x \leqslant 16 \iff \boxed{x\in\intervFF{0}{16}}$.
\end{enumerate}
\end{enumerate}
