Answer
$AB=\left[\begin{array}{cc}
{4}&{-1}\\
{-1}&{-7}\end{array}\right]$
Work Step by Step
AB is defined, since B has 4 rows,
as many as A has columns. AB is a 2x2 matrix.
$AB=$
$\left[\begin{array}{ccc}
{0 \cdot 0+(-1) \cdot 1+0 \cdot(-1)+1 \cdot 5}&
{0\cdot(-1)+(-1)\cdot 1+0\cdot 3+1\cdot 0}\\
{10\cdot 0+0\cdot 1+1\cdot(-1)+0\cdot 5}&
{10(-1)+0\cdot 1+1\cdot 3+0\cdot 0}\end{array}\right]$
$=\left[\begin{array}{cc}
{4}&{-1}\\
{-1}&{-7}\end{array}\right]$
