Given a system

\[
\begin{aligned}
{\left[\begin{array}{l}
\dot{x}_{1} \\
\dot{x}_{2} \\
\dot{x}_{3}
\end{array}ight] } & =\left[\begin{array}{rrr}
0 & -2 & 3 \\
0 & -4 & -1 \\
0 & 1 & -8
\end{array}ight]\left[\begin{array}{l}
x_{1} \\
x_{2} \\
x_{3}
\end{array}ight]+\left[\begin{array}{r}
2 \\
-8 \\
4
\end{array}ight] u \\
y & =\left[\begin{array}{lll}
4 & 1 & 6
\end{array}ight]\left[\begin{array}{l}
x_{1} \\
x_{2} \\
x_{3}
\end{array}ight]
\end{aligned}
\]

Find characteristic equation and determine if the system is stable.