Answer
$\begin{bmatrix}
-12 & 14 & 8
\end{bmatrix}
$
Work Step by Step
Adding each corresponding elements of the matrices, the given matrix expression, $
\begin{bmatrix}
-9 & 6 & 4
\end{bmatrix}
+
\begin{bmatrix}
-3 & 8 & 4
\end{bmatrix}
,$ results to
\begin{align*}
&
\begin{bmatrix}
-9+(-3) & 6+8 & 4+4
\end{bmatrix}
\\\\&=
\begin{bmatrix}
-9-3 & 6+8 & 4+4
\end{bmatrix}
\\\\&=
\begin{bmatrix}
-12 & 14 & 8
\end{bmatrix}
.\end{align*}
Hence, the given matrix operation results to $
\begin{bmatrix}
-12 & 14 & 8
\end{bmatrix}
.$
