Chapter 16.3, Problem 36PS

To determine

To find:

Elementary row operations to obtain zeros above and below the 1 in the third column without changing the entries in the first or second columns for the matrix $\left[\text{A}\right]=\left[\begin{array}{rrrr}\hfill 1& \hfill 0& \hfill -1& \hfill 5\\ \hfill 0& \hfill 1& \hfill 2& \hfill 6\\ \hfill 0& \hfill 0& \hfill 1& \hfill 4\end{array}\right]$.