Answer
(a.) $2\times 3$ matrix.
(b.) $-2$ is the element.
Work Step by Step
(a.)
The size of the matrix is equal to number of rows multiply by number of columns.
The given matrix is
$\begin{bmatrix}
4& 0&-2\\
3 & -1&5
\end{bmatrix}$
Number of rows $=2$.
and number of columns $=3$.
Hence, the size of the matrix is $2\times 3$.
(b.)
$(1,3)$ is a position at row $1$, column $3$.
The element at row $1$, column $3$ is $-2$.
Hence, the element is $-2$.
