Answer
$\begin{bmatrix} 2 & 12\\ 12& 24\\-29 &-38 \end{bmatrix}$
Work Step by Step
We can see the number of columns in first matrix is same as number of rows of a second matrix, so their product is possible.
$D= \begin{bmatrix} 1 & 2\\ 3& 0\\-6&5 \end{bmatrix} \begin{bmatrix} 4 & 8\\ -1& 2 \end{bmatrix}\\=\begin{bmatrix} 4+(-1)(2) & 8+(2)(2) \\ 12+0& 24 \\ -24-5 & -48+10 \end{bmatrix}\\=\begin{bmatrix} 2 & 12\\ 12& 24\\-29 &-38 \end{bmatrix}$
