\documentclass[a4paper,12pt]{classPres}
\usepackage{tkz-fct}

\author{}
\title{}
\date{}

\begin{document}
\begin{frame}{Questions flashs}
    Développer  et réduire l'expression
    \[ A = (x-3)\times4 - (x-3)^2\]
    Mettre sous forme canonique
    \[ B = 9x^2 - 54x + 65 \]
    \textbf{Bonus} factoriser ces 2 expressions.
\end{frame}

\begin{frame}{Correction}
    \begin{eqnarray*}
        A &=& 4x - 12 - (x^2 - 6x +9) \\
          &=& 4x - 12 - x^2 + 6x - 9 \\
          &=& -x^2 + 10x - 21
    \end{eqnarray*}
    \hline
    \begin{eqnarray*}
       B = 9x^2 - 54x + 65
    \end{eqnarray*}
    \[ \alpha = \frac{-b}{2a} = 3 \]
    \[ \beta = -\frac{b^2-4ac}{4a} = -\frac{36+38}{4} = -16 \]
    \begin{eqnarray*}
        B &=& 9(x - 3)^2 - 16 \\
    \end{eqnarray*}
\end{frame}
\begin{frame}{Bonus}
    \begin{eqnarray*}
        A &=& (x-3)\times4 - (x-3)^2\\
          &=& (x-3)(4 - x + 3)\\
          &=& (x-3)(-x + 7)
    \end{eqnarray*}
    \hline
    \begin{eqnarray*}
        B &=& 9(x - 3)^2 - 16 \\
          &=& \left[ 3(x-3) \right]^2- 4^2 \\
          &=& ( 3x - 9 - 4 ) (3x - 9 + 4) \\
          &=& (3x - 13)(3x - 5)
    \end{eqnarray*}

\end{frame}

\end{document}