2018-2019/PreStSauveur/TESL/Flash/F_18_09_10-1.tex

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\documentclass[a4paper,12pt]{classPres}
\usepackage{tkz-fct}
\author{}
\title{}
\date{}
\begin{document}
\begin{frame}{Questions flashs}
Développer et réduire l'expression
\[ A = (x-5)^2 - 7 \]
Résoudre l'inéquation
\[ x^2 - 6x - 7 > 0 \]
\end{frame}
\begin{frame}{Correction}
\begin{eqnarray*}
A &=& (x-5)^2 - 7 \\
&=& x^2 - 10x + 25 - 7 \\
&=& x^2 - 10x + 18
\end{eqnarray*}
\hline
\begin{eqnarray*}
x^2 - 6x - 7 > 0
\end{eqnarray*}
\[
\Delta = b^2 - 4ac = 64 > 0
\]
On a 2 racines
\[
x_1 = \frac{-b-\sqrt{\Delta}}{2a} = \frac{6-8}{2} = -1 \hspace{0.5cm}
x_2 = \frac{-b+\sqrt{\Delta}}{2a} = \frac{6+8}{2} = 7
\]
\end{frame}
\end{document}