Using LaTeX, how could I achieve the below:
Note how the left equations are aligned around the = which can be achieved using align*. The right case with the center text can likewise be achieved using some clever placement of \left. and \right}, however the equation sets on the left are aligned to eachother, meaning they'd have to be in one align* environment rather than one per set.
I figure I'm looking for something like a multirow for the align* or array environments.
Here a solution with multirow package, \mybrace is defined to create right brace which occupy two rows.
Code
\documentclass{article}
\usepackage{multirow}
\newcommand{\mybrace}{$\left.\vphantom{\begin{array}{c}
x \\
y
\end{array}}\right\rbrace$}
\setlength{\arraycolsep}{2pt}
\begin{document}
\[\begin{array}{rclcl}
3x+4y &=&-2 &\multirow{2}{*}{\mybrace}& \multirow{2}{*}{\parbox{4cm}
{\raggedright text text text text text text text }} \\
6x+y &=&10 & & \\[5mm]
%
x+4y &=&-2 &\multirow{2}{*}{\mybrace}& \multirow{2}{*}{\parbox{4cm}
{\raggedright text text text text text text text }} \\
y &=&10-6x& & \\[5mm]
%
3x+4(10-6x)&=&-2 &\multirow{2}{*}{\mybrace}& \multirow{2}{*}{\parbox{4cm}
{\raggedright text text text text text text text }} \\
y &=&10-6x& & \\[5mm]
\end{array}\]
\end{document}
Result
