
\exercice[style=R,N=3]{Aire d'une couronne rectangulaire}

\begin{minipage}{8cm}
\begin{tikzpicture}[yscale=0.5]
\filldraw[fill=purple!20,draw=black] (0,0) rectangle +(5,3);
\draw (-1,-1) rectangle +(7,5);
\draw[<->,>=latex] (6.5,-1) -- (6.5,4) node[midway,fill=white] {16};
\draw[<->,>=latex] (-1,-1.5) -- (6,-1.5) node[midway,fill=white] {30};
\draw[<->,>=latex] (2.5,-1) -- (2.5,0) node[right,midway] {$x$};
\draw[<->,>=latex] (2.5,3) -- (2.5,4) node[right,midway] {$x$};
\draw[<->,>=latex] (-1,1.5) -- (0,1.5) node[below,midway] {$x$};
\draw[<->,>=latex] (5,1.5) -- (6,1.5) node[below,midway] {$x$};
\end{tikzpicture}
\end{minipage}
\begin{minipage}{\dimexpr\textwidth-8.1cm}
Déterminer $x$ de sorte que l'aire de la partie blanche de la figure ci-contre soit égale à celle du rectangle plein.
\end{minipage}