# Equations with justifications in angle brackets in Latex

How would I do something like this :

    f(x)
=      < Justification >
x + y + a
=      < according to ... >
abc


Which math environment should I use get this kind of equations? And how can I display 2 such blocks side by side?

## 1 Answer

I would do it like this (this saves space too).

\documentclass{article}
\usepackage{mathtools}
\begin{document}
\begin{alignedat} {4} f(x) &= x + y + a & \qquad & \text{(You say it)}\\ &= abc & \qquad & \text{(According to me)} \end{alignedat}
\end{document}


• amsmath is enough and the second \qquad isn't needed. – Svend Tveskæg Feb 20 '14 at 2:46
• @SvendTveskæg Well, I always use mathtools (habit) and use of \qquad is always subjective. Anyway, thanks for the comment. – user11232 Feb 20 '14 at 6:38