Answer
$\left[\begin{array}{lll}
-12 & 14 & 0\\
2 & -14 & 18
\end{array}\right]$
Work Step by Step
If $A$ is a matrix and $c$ is a scalar, then $cA$ is the matrix formed by multiplying each element in $A$ by $c$.
$-2A=\left[\begin{array}{lll}
-4 & 2 & -4\\
-10 & -6 & 2
\end{array}\right],\quad 4D=\left[\begin{array}{lll}
-8 & 12 & 4\\
12 & -8 & 16
\end{array}\right]$
To add two matrices, they must have the same order.
The resulting matrix has elements obtained by adding the corresponding elements of the two matrices.
$-2A$ and $4D$ are both $2\times 3$ matrices, so their sum exists.
$-2A+4D=\left[\begin{array}{lll}
-4-8 & 2+12 & -4+4\\
-10+12 & -6-8 & 2+16
\end{array}\right]$
$=\left[\begin{array}{lll}
-12 & 14 & 0\\
2 & -14 & 18
\end{array}\right]$
