Question
Classify the following matrices as a row, a column, a square, a diagonal, a scalar, a unit, an upper triangular, a lower triangular, a symmetric or a skew- symmetric matrix :
$\left[\begin{array}{ccc}3 & -2 & 4 \\ 0 & 0 & -5 \\ 0 & 0 & 0\end{array}\right]$