
\bigskip

\exercice[style=A,N=1,verif]{\`A partir d'un graphique}

Donner l'équation réduite de chacune des droites représentées dans le repère suivant en lisant directement sur le graphique le coefficient directeur et l'ordonnée à l'origine.

\medskip

\begin{center}
\begin{tikzpicture}[scale=.7]
\draw[gray] (-5,-5) grid (5,5);
\draw[thick,->,>=stealth'] (-5,0) -- (5,0);
\draw[thick,->,>=stealth'] (0,-5) -- (0,5);
\clip (-5,-5) rectangle (5,5);
\tkzDefPoint(-3,4){A}
\tkzDefPoint(3,1){B}
\tkzDrawPoints[color=red](A,B)
\tkzLabelPoints[color=red,above](A,B)
\tkzDrawLine[add=0.5 and 0.5,color=red](A,B)
\fill[red] (0,2.5) circle (2pt) node[above right,scale=0.75] {2,5};

\tkzDefPoint(-2,-1){C}
\tkzDefPoint(4,3){D}
\tkzDrawPoints[color=blue](C,D)
\tkzLabelPoints[color=blue,above](C,D)
\tkzDrawLine[add=0.5 and 0.5,color=blue](C,D)
\fill[blue] (0,0.333) circle (2pt) node[right,scale=0.66,inner xsep=5pt] {$\frac{1}{3}$};

\tkzDefPoint(-4,3){E}
\tkzDefPoint(-4,-4){F}
\tkzDrawPoints[color=green!50!black](E,F)
\tkzLabelPoints[color=green!50!black,left](E,F)
\tkzDrawLine[add=0.5 and 0.5,color=green!50!black,line width=1.5pt](E,F)

\tkzDefPoint(-3,-2){G}
\tkzDefPoint(2,-2){H}
%\tkzDrawPoints[color=purple](G,H)
\fill[purple] (G) circle (2pt);
\fill[purple] (H) circle (2pt);
\tkzLabelPoints[color=purple,below](G,H)
\tkzDrawLine[add=0.5 and 0.5,color=purple,line width=1.5pt](G,H)

\foreach \x in {-4,-3,-2,-1,0,1,2,3,4} 
{
\node[below left,scale=0.75] at (\x,0) {$\x$};
\node[below left,scale=0.75] at (0,\x) {$\x$};
}
\end{tikzpicture}
\end{center} 