find the general solution of the given system
\( \mathbf{X}^{\prime}=\left(\begin{array}{lll}1 & 1 & 1 \\ 0 & 2 & 3 \\ 0 & 0 & 5\end{array}\right) \mathbf{X}+\left(\begin{array}{r}1 \\ -2 \\ 2\end{array}\right) e^{4 t} \quad \) Use the method of