%%
%% An UIT Edition example
%%
%% Example 10-04-4 on page 205.
%%
%% 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
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\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{375.57637pt}
\AtBeginDocument{\setlength\parindent{0pt}}
\setcounter{equation}{2}
\renewcommand\theequation{10.\arabic{equation}}
\StartShownPreambleCommands
\usepackage{amsmath,color}
\StopShownPreambleCommands
\begin{document}
\begin{align}
y &= 2x^2 -3x +5\nonumber\\
& \hphantom{= \ 2\left(x^2-\frac{3}{2}\,x\right. }%
\textcolor{blue}{%
\overbrace{\hphantom{+\left(\frac{3}{4}\right)^2- %
\left(\frac{3}{4}\right)^2}}^{=0}}\nonumber\\[-11pt]
&= 2\left(\textcolor{red}{%
\underbrace{x^2-\frac{3}{2}\,x + \left(\frac{3}{4}\right)^2}}
\underbrace{-\left(\frac{3}{4}\right)^2 + \frac{5}{2}}\right)\\
&= 2\left(\qquad\textcolor{red}{\left(x-\frac{3}{4}\right)^2}
\qquad + \ \frac{31}{16}\qquad\right)\nonumber\\
y\textcolor{blue}{{}-\frac{31}{8}}
&= 2\left(x\textcolor{cyan}{{}-\frac{3}{4}}\right)^2\nonumber\\
&\Rightarrow S\left(\frac{3}{4}\right|\left.\frac{31}{8}\right)\nonumber
\end{align}
\end{document}
