%% 
%%  An UIT Edition example
%% 
%%  Example 06-11-1 on page 104.
%% 
%%  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}
\setcounter{section}{11}
\setcounter{equation}{50}
\renewcommand\theequation{eq. \roman{section}-\Roman{equation}}}
\usepackage{blkarray}
\newcommand\bigstrutht{\vrule width0pt height 12pt depth0pt\relax}
\newcommand\bigstrutdp{\vrule width0pt height 0pt depth5pt\relax}
\StartShownPreambleCommands
\usepackage{amsmath,blkarray}
\renewcommand\theequation{eq. \roman{section}-\Roman{equation}}
\StopShownPreambleCommands
\begin{document}
\begin{align}\begin{blockarray}{*{4}{c}}
  \begin{block}{[ccc]c}
    \bigstrutht 1-\lambda x & 0 & 0 & \ell_1 \\  0 & 1-\lambda x & 0 & \ell_2 \\
    \bigstrutdp 0 & 0 & 1-\lambda x & \ell_3 \\
  \end{block}
  c_1 & c_2 & c_3
\end{blockarray}\end{align}
\end{document}
