\documentclass[12pt] {article} \usepackage[T1]{fontenc} 
\usepackage[utf8]{inputenc}
\usepackage{amsmath,amssymb,graphicx,multicol,mathrsfs, fancyhdr,enumerate,fourier,eurosym,enumerate,tabularx,variations,numprint}
\usepackage[dvips]{color}
\usepackage[tikz]{bclogo}
\usepackage{pst-plot,pst-tree,pstricks,pst-node,pstricks-add,pst-math,pst-xkey,pst-eucl}
\usepackage[francais]{babel} 
\everymath{\displaystyle}
%\usepackage[colorlinks=true,pdfstartview=FitV,linkcolor=blue,citecolor=blue,urlcolor=blue]{hyperref}
\textwidth 19cm \textheight 24cm \hoffset 
-1,4cm \voffset -3.7cm \oddsidemargin 0pt 
\renewcommand{\thesubsection}{\textcolor{blue}{\Roman{subsection}}} 
\renewcommand{\thesubsubsection}{\textcolor{blue}{\Roman{subsection}}.\textcolor{blue}{\arabic{subsubsection}}} 
      \newtheorem{exercice}{Exercice}
      \newtheorem{solution}{Solution}
\pagestyle{empty}
% pour le pied de page central
\cfoot{Page \thepage/\pageref{fin}}

\begin{document}
%\tableofcontents

\begin{center}
\section*{\textcolor{red}{Exercices de développements}}

\end{center}




\subsection{\textcolor{blue}{Développements directs}}
     Déterminez la forme développée de chacune des expressions suivantes.

\begin{exercice}
$f(x)=(2x+3)(4x+5)$.
\end{exercice}

\begin{exercice}
$f(x)=(3x-1) (2x+3)$.
\end{exercice}


\begin{exercice}
$f(x)=(-10 x-1) (9-8 x)$.
\end{exercice}

\begin{exercice}
$f(x)=(-10 x-6) (x+8)$.
\end{exercice}

\begin{exercice}
$f(x)=(-9 x-1) (x-2)$.
\end{exercice}

\begin{exercice}
$f(x)=(-10 x-1) (-7 x-5)$.
\end{exercice}

\begin{exercice}
$f(x)=(4-9 x) (-3 x-4)$.
\end{exercice}

\subsection{\textcolor{blue}{Identités remarquables}}
     Déterminez la forme développée de chacune des expressions suivantes.
     
\begin{exercice}

$f(x)=(x-1) (x+1)$.
\end{exercice}

\begin{exercice}

$f(x)=(9 x+5)^2$.
\end{exercice}

\begin{exercice}

$f(x)=(5 x-4)^2$.
\end{exercice}

\begin{exercice}

$f(x)=(4+6x) (4-6 x)$.
\end{exercice}

\begin{exercice}

$f(x)=(4-x)^2$.
\end{exercice}

\begin{exercice}

$f(x)=(4 x+2)^2$.
\end{exercice}

\begin{exercice}

$f(x)=(-7 x-5) (-7 x+5)$.
\end{exercice}



\end{document}