Item1.2.5.2.c

The reduced row echelon form is

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

and this linear system has a single solution.

in-context