\begin{exercice}
Résoudre dans $\mathbb{R}$ les systèmes.
\begin{colenumerate}{2}
\item $\left\{\begin{array}{ccc}
\e^{x-1}+\e^{y} & = & 2 \\
\e^{x}-\e^{y+1} & = & 0
\end{array}\right.$
\item $\left\{\begin{array}{ccc}
\e^{x+2}+2\e^{y-3} & = & 3 \\
\e^{x}\e^{y} & = & \e
\end{array}\right.$
\item $\left\{\begin{array}{ccc}
\e^{x}+\e^{y} & = & 2 \\
x+y  & = & 0
\end{array}\right.$
\item $\left\{\begin{array}{ccc}
xy & = & 3 \\
\e^{x+1}\e^{y+1} & = & 1
\end{array}\right.$
\end{colenumerate}
\end{exercice}

