Answer
$\left[\begin{array}{cc}
{9}&{2}\\
{34}&{13}\\
{47}&{20}\end{array}\right]$
Work Step by Step
Let $A$ denote an $m$ by $\fbox{$r$}$ matrix and let $B$ denote an $\fbox{$r$}$ by $n$ matrix.
The product $AB$ is defined as the $m$ by $n$ matrix whose entry in row $i,$ column $j$
is the product of the $i$ th row of $A$ and the $j$ th column of $B$ .
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$A$ is a $3$ by $\fbox{$3$}$ matrix and B is a $\fbox{$3$}$ by $2$ matrix.
The product $AB$ is defined, and is a $3$ by $2$ matrix.
$AB=\left[\begin{array}{ll}
{1(1)+0(6)+1(8)}&{1(3)+0(2)+1(-1)}\\
{2(1)+4(6)+1(8)}&{2(3)+4(2)+1(-1)}\\
{3(1)+6(6)+1(8)}&{3(3)+6(2)+1(-1)}\end{array}\right]$
$=\left[\begin{array}{cc}
{9}&{2}\\
{34}&{13}\\
{47}&{20}\end{array}\right]$