%%
%% An UIT Edition example
%%
%% Example 09-12-1 on page 177.
%%
%% 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{equation}{5}
\renewcommand\theequation{9.\arabic{equation}}
\StartShownPreambleCommands
\usepackage{amsmath,empheq,xcolor,graphicx}
\newcommand*\mycolbox[1]{%
\colorbox{blue!30!yellow!40}{\hspace{1em}#1\hspace{1em}}}
\StopShownPreambleCommands
\begin{document}
\begin{subequations}
\begin{empheq}[% start of options
box=\mycolbox,
right={\;\makebox[.9em]{$\raisebox{-.5\totalheight+\fontdimen22\textfont2}
{\resizebox{!}{\EmphEqdisplayheight+\EmphEqdisplaydepth}{!}}$}},
left={X=Y\Rightarrow\empheqlbrace}]{alignat=3}
%
A_1&=b_1 & \qquad c_1&=d_1 & \qquad e_1&= f_1
\tag*{\_A\raisebox{1ex}{silly}\raisebox{-1ex}{tag}\_}\\
A_2&=b_2 & \qquad c_2&=d_2 & \qquad e_2&= f_2 \\
A_3&=b_3 & \qquad c_3&=d_3 & \qquad e_3&= f_3
\end{empheq}
\end{subequations}
\end{document}
