[texhax] 3x3 array of alighned equations

[Barbara Beeton]

    The alignat environment works a treat except now I'd like to get the
    subequation numbering working.

if you're using amsmath, just wrap the commands

\begin{subequations}
...
\end{subequations}

around any multi-line equation structure.  this is
described in the amsmath user's guide (amsldoc), which
is included in the package as a pdf file as well as
source.
							-- bb