# Box part of equation in align environment

I want to box, as an answer, an equation of the align* environment. Not sure how to do it.

\begin{align*}
(1+2i)z_2&=-11(2-i)\\
z_2&=\dfrac{11(i-2)}{1+2i}\\
z_2&=11i
\end{align*}


I have tried \boxed{z_2&=11i}, but it failed.

You can use the \Aboxed macro from the mathtools package to have a box around a single alignment point &, i.e. a single line in your case:

\documentclass[preview,border=10pt]{standalone}
\usepackage{mathtools}

\begin{document}

\begin{align*}
(1+2i)z_2&=-11(2-i)\\
z_2&=\dfrac{11(i-2)}{1+2i}\\
\Aboxed{z_2&=11i}
\end{align*}

\end{document}


• This is for an individual line in an alignment, as far as I know. – Bernard Mar 30 '16 at 9:16
• @Bernard Yes, I thought that was what OP was after, seeing as he tried \boxed{...}. The frame around the output is added later, I will change that to make it clearer :) – sodd Mar 30 '16 at 9:18