alignment of equations

Question

how can I display the equations like this? I tried \begin{aligned} but its all centered.flalign is showing errors as well

Answer 1

How about this?

\documentclass[fleqn]{article}
\usepackage{amsmath}
\begin{document}
\begin{equation}
  \begin{split}
    a &= b, a = b, a = b,\\
    a &= b, \\
    a &= b, a = b, \\
    a &= b, a = b, a = b,
  \end{split}
\end{equation}
where
\begin{equation}
  \begin{split}
    a &= b,\\
    a &= b, a = b,\\
    a &= b, a = b, a = b \\
    a &= b, a = b.
  \end{split}
\end{equation}

\end{document}

Answer 2

This left aligns ALL the equations. You can center them using &&& instead of & before aligned, but this looks more like the original.

\documentclass[fleqn]{article}
\usepackage{amsmath}
\begin{document}
\begin{align}
  &\begin{aligned}
    a &= b, a = b, a = b,\\
    a &= b, \\
    a &= b, a = b, \\
    a &= b, a = b, a = b,
  \end{aligned}
\intertext{where}
  &\begin{aligned}
    a &= b,\\
    a &= b, a = b,\\
    a &= b, a = b, a = b, a=b \\
    a &= b, a = b.
  \end{aligned}
\end{align}

\end{document}