Unwanted space before flalign

Question

Why is there so much vertical space between the subsection heading and the equation in the following example. How do I get rid of it?

\documentclass{article}
\usepackage{mathtools}
\begin{document}
\section{Title}
\subsection{Subtitle}
\begin{flalign*}
a+b=8 &&\\
c=2 &&
\end{flalign*}
\end{document}

Secondly, why is it aligned at the equals sign, even without &=? I want both of the lines to be flushed to the left.

Answer 1

Reduce \abovedisplayskip and put a & at the begining and one at the end.

\documentclass{article}
\usepackage{mathtools}
\begin{document}
\section{Title}
\subsection{Subtitle}
{\setlength{\abovedisplayskip}{0pt}
\begin{flalign*}
&a+b=8 &\\
&c=2 &
\end{flalign*}}
\end{document}

Answer 2

I'm not sure that you really want flalign for this:

\documentclass{article}
\usepackage{array}
\newenvironment{flusheqs}
 {\noindent$\begin{array}{@{}>{\displaystyle}l@{}}}
 {\end{array}$\par}


\begin{document}
\section{Title}
\subsection{Subtitle}
\begin{flusheqs}
a+b=8 \\
c=2
\end{flusheqs}
\end{document}