[Tex/LaTex] One-line equation with two columns

equationshorizontal alignmentmath-mode

I try to write an equation with two similar formulas, i.e.

\begin{equation}
\qquad A_1 = B + C \qquad A_2 = D + E \qquad
\end{equation}

Of course, instead of \qquads I want to use something like \hfill.

I would also like to do the same with some text within, like

\begin{equation}
\qquad A_1 = B + C \quad \text{and} \quad A_2 = D + E \qquad
\end{equation}

Is there any prefered/"best" way for this?

Best Answer

amsmath's align environment provides this by default:

enter image description here

\documentclass{article}
\usepackage{amsmath}% http://ctan.org/pkg/amsmath
\begin{document}
\noindent X\dotfill X
\begin{align}
  A_1 &= B + C & A_2 &= D + E
\end{align}
\begin{align}
  A_1 &= B + C &&\text{and} & A_2 &= D + E
\end{align}
\noindent X\dotfill X
\end{document}