find the general solution to the given equation
\begin{equation}
9y''+6y'+y=0
\end{equation}we get
\begin{equation}
9r^2+6r+1=0
\end{equation}solve for r, we have
\begin{equation}
3r+1=0, r = -1/3
\end{equation} so we have
\begin{equation}
y(t) = C1e^{-1/3}+C2te^{-1/3}
\end{equation}