###### Item d

The row equivalent reduced row echelon form is

\begin{equation*}
\left[
\begin{array}{rrr|r}
1 \amp 0 \amp 4 \amp 2 \\
0 \amp 1 \amp 3 \amp 2 \\
0 \amp 0 \amp 0 \amp 0 \\
\end{array}
\right].
\end{equation*}

There are infinitely many solutions.