If [tex]A[/tex] is the matrix product
[tex]A=\underbrace{\begin{pmatrix}1&2\\4&3\end{pmatrix}}_{M_1}\underbrace{\begin{pmatrix}6&1&5\\7&3&4\end{pmatrix}}_{M_2}[/tex]
and [tex]a_{2,3}[/tex] is the entry of [tex]A[/tex] in the second row and third column, then
[tex]a_{2,3}=\begin{pmatrix}4&3\end{pmatrix}\begin{pmatrix}5\\4\end{pmatrix}=4\times5+3\times4=\boxed{32}[/tex]
That is, the 2nd row, 3rd column entry of [tex]A[/tex] is the product of the 2nd row of [tex]M_1[/tex] and the 3rd column of [tex]M_2[/tex].
