Chapter 11.1, Problem 18E

To determine

(a)

Whether the matrix $\left[\begin{array}{cccc}1& 0& 0& 1\\ 0& 1& 0& 2\\ 0& 0& 1& 3\end{array}\right]$ is in row-echelon form.

To determine

(b)

Whether the matrix $\left[\begin{array}{cccc}1& 0& 0& 1\\ 0& 1& 0& 2\\ 0& 0& 1& 3\end{array}\right]$ is in reduced row-echelon form.

To determine

(c)

To write:

The system of equations for the matrix $\left[\begin{array}{cccc}1& 0& 0& 1\\ 0& 1& 0& 2\\ 0& 0& 1& 3\end{array}\right]$.