###### Item 1.2.5.2.d

The reduced row echleon form is

\begin{equation*}
\left[
\begin{array}{rrrr|r}
1 \amp 0 \amp 0 \amp 1 \amp 0 \\
0 \amp 1 \amp 0 \amp 0 \amp 3 \\
0 \amp 0 \amp 1 \amp 0 \amp -1 \\
\end{array}
\right]\text{,}
\end{equation*}

and there are infinitely many solutions.