\begin{exercice}
      Factoriser, puis étudier le signe des expressions suivantes.
      \begin{enumerate}
      \item
        $\left(x-3\right)\left(2-3x\right)-\left(x-1\right)\left(x-3\right)$
      \item $x^2-3x$
      \item $9-{4x}^2$
      \item $x^2+8x+16$
      \end{enumerate}
    \end{exercice}
    \begin{corrige}
      \begin{enumerate}
      \item 

        \begin{tikzpicture}[scale=0.7,general]
          \tkzTabInit[lgt=1.85,espcl=1.15, lw=0.3mm, color, colorC=H4,
          colorV=H4, colorL=H4, colorT=A4]
          {$x$/1.25, $x-1$/.85 , $3-4x$/.85 , $f(x)$/.85}
          {$-\infty$, $\dfrac{3}{4}$ , $1$ , $+\infty$}
          \tkzTabLine{, - , t , - , z , +}
          \tkzTabLine{, + , z , - , t , -}
          \tkzTabLine{, - , z , + , z , -}
        \end{tikzpicture}

      \item 

        \begin{tikzpicture}[scale=0.7,general]
          \tkzTabInit[lgt=1.85,espcl=1.15, lw=0.3mm, color, colorC=H4,
          colorV=H4, colorL=H4, colorT=A4]
          {$x$/1.25, $x$/.85 , $x-3$/.85 , $f(x)$/.85}
          {$-\infty$, $0$ , $3$ , $+\infty$}
          \tkzTabLine{, - , z , + , t , +}
          \tkzTabLine{, - , t , - , z , +}
          \tkzTabLine{, + , z , - , z , +}
        \end{tikzpicture}

      \item 

        \begin{tikzpicture}[scale=0.7,general]
          \tkzTabInit[lgt=1.85,espcl=1.15, lw=0.3mm, color, colorC=H4,
          colorV=H4, colorL=H4, colorT=A4]
          {$x$/1.25, $3-2x$/.85 , $3+2x$/.85 , $f(x)$/.85}
          {$-\infty$, $-\dfrac{2}{3}$ , $\dfrac{2}{3}$ , $+\infty$}
          \tkzTabLine{, + , t , + , z , -}
          \tkzTabLine{, - , z , + , t , +}
          \tkzTabLine{, - , z , + , z , -}
        \end{tikzpicture}
      \item $(x + 4)^2 \geq 0$, quelque soit $x \in \R$
      \end{enumerate}
    \end{corrige}