# Align equations at more than one point

I have got the following set of equations: which corresponds to the following code:

 \begin{align}
\begin{split}
a_1 + b_1 \xi + c_1 \xi^2 + d_1 \xi^3 &= a_2 + b_2 \xi + c_2 \xi^2 + d_2 \xi^3 \\
b_1 + 2c_1 \xi + 3d_1 \xi^2 &= b_2 + 2c_2 \xi + 3d_2 \xi^2 \\
2 c_1 + 6 d_1 \xi &= 2c_2 + 6 d_2 \xi,
\end{split}
\end{align}


I want all three equations to start at the same point, such that it would look something like this: Is this possible?

• use \begin{alignedat}{2}+\end{alignedat} instead of split, place & at the start of every row, and && before the =. – daleif Jul 31 at 9:40
• Next time please make sure to post full minimal examples including document class and a minimal preamble. That makes it a lot easier to test your code. Here we have to guess a lot of stuff before being able to test it. – daleif Jul 31 at 9:41
• BTW: I'd probably use equation at the outer layer, not align – daleif Jul 31 at 9:42
• You could also minipage it, if you know the endpoint of your equations. – Bart Jul 31 at 9:43
• Awesome, this works; thank you daleif! Next time I will include the document class etc :) – Rik Jul 31 at 9:43

Just use alignedat instead of split and keep track of the &'s

\documentclass[a4paper]{article}
\usepackage{amsmath}
\begin{document}
\begin{equation}
\begin{alignedat}{2}
&a_1 + b_1 \xi + c_1 \xi^2 + d_1 \xi^3 &&= a_2 + b_2 \xi + c_2 \xi^2 + d_2 \xi^3 \\
&b_1 + 2c_1 \xi + 3d_1 \xi^2 &&= b_2 + 2c_2 \xi + 3d_2 \xi^2 \\
&2 c_1 + 6 d_1 \xi &&= 2c_2 + 6 d_2 \xi,
\end{alignedat}
\end{equation}
\end{document}