%% 
%%  An UIT Edition example
%% 
%%  Example 09-16-6 on page 183.
%% 
%%  Copyright (C) 2010 Herbert Voss
%% 
%%  It may be distributed and/or modified under the conditions
%%  of the LaTeX Project Public License, either version 1.3
%%  of this license or (at your option) any later version.
%% 
%%  See http://www.latex-project.org/lppl.txt for details.
%% 
%% 
%% ==== 
% Show page(s) 1
%% 
\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{375.57637pt}
\AtBeginDocument{\setlength\parindent{0pt}}
\StartShownPreambleCommands
\usepackage{gauss}  \renewcommand\rowmultlabel[1]{|\,\times#1}
\StopShownPreambleCommands
\begin{document}
\[\begin{gmatrix}
 1 &-2 & 1 & 2 & & 8 \\  2 & 3 &-2 & 3 & & 14\\ % rows 0 and 1
 4 &-1 & 3 &-1 & & 7 \\  3 & 2 &-4 & 5 & & 5 \\ % 2 and 3
                     \\
 1 &-2 & 1 & 2 & & 8 \\  0 & 7 &-4 &-1 & &-2 \\ % 5 and 6
 0 & 7 &-1 &-9 & &-25\\  0 & 8 &-7 &-1 & &-9 \\ % 7 and 8
                     \\
 1 &-2 & 1 & 2 & & 8 \\  0 & 7 &-4 &-1 & &-2 \\ % 10 and 11
 0 & 0 & 3 &-8 & &-23\\  0 & 0 &-17& 1 & &-47\\ % 12 and 13
                     \\
 1 &-2 & 1 & 2 & & 8 \\  0 & 7 &-4 &-1 & &-2 \\ % 15 and 16
 0 & 0 & 3 &-8 & &-23\\  0 & 0 & 0 &-\frac{133}{3}& &\frac{-532}{3} % 17 and 18
\rowops
\mult{0}{(-2)}\add{0}{1}\mult{0}{(-4)}\add{0}{2}\mult{0}{(-3)}\add{0}{3}% matrix 1
\mult{6}{(-1)}\add{6}{7}\mult{6}{(-\frac{8}{7})}\add{6}{8}% matrix 2
\mult{12}{\frac{17}{3}}\add{12}{13} % matrix 3
\end{gmatrix} \]
\end{document}