###### Item a

The row equivalent reduced row echelon form is

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

and there are infinitely many solutions.

The row equivalent reduced row echelon form is

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

and there are infinitely many solutions.