I have a homework document using 2-column article document class as follows.
\documentclass[twocolumn]{article}
\usepackage[a4paper,margin=1cm]{geometry}
\usepackage{amsmath}
\begin{document}
\begin{enumerate}
\item The degree of (C) is 3.
\item The degree of (A) is 1.
\item
$
\begin{aligned}[t]
\begin{split}
-3x(x+1)&-2x(x-1) \\
&+4(x^2-3x-1)
\end{split}
&=
\begin{split}
-3x^2&-3x-2x^2+2x\\
&+4x^2-12x-4
\end{split}\\
&= -x^2-13x-4
\end{aligned}
$
\end{enumerate}
\end{document}
What I want to achieve are:
- the long equation is split in both LHS and RHS.
- the
=
is consistently aligned.
The output I want to achieve roughly looks like the following "screenshot".
The red lines represent the first two items and the green one represents the long equation. The black line represents the hypothetical column separator.
How to construct a long equation that is split in LHS and RHS to occupy a narrow column?
Best Answer
This is based on mafp's answer, but doesn't use
aligned
in the left. Note the\!
in front of\begin{aligned}
and the{}+
, which are needed for proper spacing!