\left [ 
\begin{array}{ccc} 
\begin{array}{cc}
1 & -3 \\
-\frac{2}{3} & 2 \\
4 & -3
\end{array} & 
\left |
\begin{array}{c}
4 \\
5 \\
b
\end{array}
\end{array}
\right ]\sim
\left [ 
\begin{array}{ccc} 
\begin{array}{cc}
1 & -3 \\
0 & 9 \\
0 & 0
\end{array} & 
\left |
\begin{array}{c}
4 \\
-16+b \\
\frac{23}{3}
\end{array}
\end{array}
\right ].