line number correcting in math display - command form

I'd love to make this an environment so I could do begin and end, I couldn't figure this out.

But I do have these options (one acts like equation* the other like eqnarray*)

 %analog for this - begin Line Number; end Line Number
%--------------------------------
\newcommand{\bLN}{\begin{linenomath*} \begin{equation*}}
\newcommand{\eLN}{\end{equation*} \end{linenomath*}}
%--------------------------------






%analog for this - begin Array Line Number; end Array Line Number
%--------------------------------
\newcommand{\baLN}{\begin{linenomath*} \begin{eqnarray*}}
\newcommand{\eaLN}{\end{eqnarray*} \end{linenomath*}}
%--------------------------------
%usage:
%\bLN
%a = b
%\eLN

\baLN
3 &=& 4 \\
&=& 7
\eaLN