# [Tex/LaTex] Align equations within one line

alignamsmath

I would like to align multiple equations (with one rather long one) within one line of my document with \begin{align}. But using "&" for spacing causes rather too long spaces and weird right alignment for some parts. It causes my equation enumeration in the document to be placed in the next empty line. I am using amsmath with the fleqn option.

I hope my problem gets clearer with my code:

\documentclass[]{scrbook}
\usepackage[fleqn]{amsmath}
\usepackage{amssymb}

\begin{document}
{\setlength{\mathindent}{0cm}

\begin{subequations}\label{eq:MINLP}

\begin{align}
\tag{\ref{eq:MINLP}}\\

M_{n,j,k}^{up}(1-\delta_{n,k}) && n \,  \epsilon \, \mathcal{N}_{b},\,
k \,  \epsilon \,  \mathcal{F},\, j \,  \epsilon  \, \mathcal{E} \\

& f_{j,k}(V_{n,j},V_{2n,j},V_{2n+1,j}) \ge M_{n,j,k}^{lo}
(1-\delta_{n,k}) && n=a+b \\

\end{align}
\end{subequations}}
\end{document}


I would like to push the part starting with "n…" further to the left but still be aligned, such that the equation enumeration 3.1a will be in the same line.

The posted code does not have the spacing shown, but generates errors due to the blank lines, this version runs without error

\documentclass[]{scrbook}
\usepackage[fleqn]{amsmath}
\usepackage{amssymb}

\begin{document}
%\setlength{\mathindent}{0cm}

\begin{subequations}\label{eq:MINLP}

\begin{align}
\min &\sum_{j=1}^{NE}(y_{j}-V_{1,j})^{2}
\tag{\ref{eq:MINLP}}\\