\documentclass[a4paper,10pt]{article}
\usepackage{myXsim}

\title{Graphiques des fonctions puissances}
\tribe{Terminale ES}
\date{Octobre 2019}

\pagestyle{empty}

\newcommand\repgraph{%
\begin{tikzpicture}[baseline=(a.north), xscale=1.5, yscale=0.7]
    \tkzInit[xmin=-5,xmax=5,xstep=1,
    ymin=0,ymax=10,ystep=1]
    \tkzGrid
    \tkzAxeXY
    \tkzFct[domain = -5:5,color=red,very thick]%
    {0.5**x}
    \tkzFct[domain = -5:5,color=green,very thick]%
    {0.8**x}
    \tkzFct[domain = -5:5,color=blue,very thick]%
    {2**x}
    \tkzFct[domain = -5:5,color=black,very thick]%
    {1.5**x}
\end{tikzpicture}

}
\begin{document}

\repgraph
\vfill
\repgraph
\vfill
\repgraph


\end{document}