Answer
$\begin{bmatrix}
{6}&{14}&{-14}\\
{2}&{27}&{-18}\\
{3}&{0}&{33}\end{bmatrix}$
Work Step by Step
In Problem 17, we found : $CA=\left[\begin{array}{ccc}
{1}&{14}&{-14}\\
{2}&{22}&{-18}\\
{3}&{0}&{28}\end{array}\right]$
Now, $5I_{3}=5\begin{bmatrix}
1 & 0 & 0\\
0 & 1 & 0\\
0 & 0 & 1
\end{bmatrix}=\begin{bmatrix}
5 & 0 & 0\\
0 & 5 & 0\\
0 & 0 & 5
\end{bmatrix}$
Next, $CA+5I_{3}=\left[\begin{array}{ccc}
{1}&{14}&{-14}\\
{2}&{22}&{-18}\\
{3}&{0}&{28}\end{array}\right]+\begin{bmatrix}
5 & 0 & 0\\
0 & 5 & 0\\
0 & 0 & 5
\end{bmatrix}\\=\left[\begin{array}{ccc}
{1+5}&{14}&{-14}\\
{2}&{22+5}&{-18}\\
{3}&{0}&{28+5}\end{array}\right]=\begin{bmatrix}
{6}&{14}&{-14}\\
{2}&{27}&{-18}\\
{3}&{0}&{33}\end{bmatrix}$
