Leading Coefficient of Matrix/Examples

Examples of Leading Coefficient of Matrix
Consider:
 * $\mathbf A = \begin {bmatrix}

1 & 5 & 4 & 2 \\ 0 & 0 & 5 & 7 \\ 0 & 6 & 0 & 9 \\ 0 & 0 & 0 & 0 \\ \end {bmatrix}$

The leading coefficient of row $1$ is $1$.

The leading coefficient of row $2$ is $5$.

The leading coefficient of row $3$ is $6$.

Row $4$ has no leading coefficient.