Answer
$\begin{bmatrix}
1 & 0 & 0\\
0 & 1 & 0\\
0 & 0 & \frac{7}{2}\\
\end{bmatrix}$
AB is a 3×3 matrix
Work Step by Step
A is a 3×3 matrix, and B is a 3×3 matrix. The number of columns of A is equal to the number of rows of B. So, it is possible to find AB, where AB is a 3×3 matrix.
$\begin{bmatrix}
5(\frac{1}{5}) + 0(0) + 0(0) & 5(0) + 0(-\frac{1}{8}) + 0(0) & 5(0) + 0(0) + 0(\frac{1}{2})\\
0(\frac{1}{5}) + (-8)(0) + 0(0) & 0(0) + (-8)(-\frac{1}{8}) + 0(0) & 0(0) + (-8)(0) + 0(\frac{1}{2})\\
0(\frac{1}{5}) + 0(0) + 7(0) & 0(0) + 0(-\frac{1}{8}) + 7(0) & 0(0) + (0)(0) + 7(\frac{1}{2})
\\
\end{bmatrix}$ = $\begin{bmatrix}
1 & 0 & 0\\
0 & 1 & 0\\
0 & 0 & \frac{7}{2}\\
\end{bmatrix}$
