avoid eq. # on \shortintertext{} from mathtools

Question

Does anyone know of an elegant way to avoid having to manually put an \nonumber at the end of \shortintertext{} when it is at the last line? As illustrated by the parts of the minimal working example (MWE) below that is commented out by a %.

I am very happy to use \shortintertext{} from mathtools. \shortintertext{} do not produce a equation number, which I like, but if I use \shortintertext{} as the last thing in an {align} equation block \shortintertext{} produces an extra equation number (as this, see blow for MWE)

It also seems as \shortintertext{} produces extra line spacing …

MWE (inspired by this SE example);

\documentclass[preview]{standalone}
\usepackage{mathtools}
\usepackage[usenames,dvipsnames]{xcolor}

\begin{document}
\begin{align}
\shortintertext{\color{gray}  We are trying to solve for $x$}
    3+x &=4\\
\shortintertext{\color{gray} Subtract 3 from both sides:} 
    x &=4-3 \
 \shortintertext{\color{gray} Hence, $x$ must be 1:}
    x &=1 
 \shortintertext{\color{gray} Some comments on the conclussion} % \nonumber
\end{align} %  \vspace{-3.4 em}
\end{document} 

Answer 1

You can use a different approach:

\documentclass{article}
\usepackage{mathtools}
\usepackage[usenames,dvipsnames]{xcolor}

\newenvironment{compactequations}
 {\setlength{\abovedisplayskip}{2pt plus 2pt}%
  \setlength{\abovedisplayshortskip}{2pt plus 2pt}%
  \setlength{\belowdisplayskip}{2pt plus 2pt}%
  \setlength{\belowdisplayshortskip}{2pt plus 2pt}}
 {}

\begin{document}

\begin{compactequations}
\noindent\textcolor{gray}{We are trying to solve for $x$}
\begin{align}
    3+x &=4\\
\intertext{\color{gray} Subtract 3 from both sides:} % \nonumber
    x &=4-3 \\
 \intertext{\color{gray} Hence, $x$ must be 1:}
    x &=1
\end{align}
\textcolor{gray}{Some comments on the conclusion}
\end{compactequations}

\end{document}

Without aligning at the equals signs:

\documentclass{article}
\usepackage{mathtools}

\newenvironment{compactequations}
 {\setlength{\abovedisplayskip}{2pt plus 2pt}%
  \setlength{\abovedisplayshortskip}{2pt plus 2pt}%
  \setlength{\belowdisplayskip}{2pt plus 2pt}%
  \setlength{\belowdisplayshortskip}{2pt plus 2pt}}
 {}

\begin{document}

\begin{compactequations}
\noindent We are trying to solve for $x$
\begin{equation}
    3+x=4
\end{equation}
Subtract 3 from both sides:
\begin{equation}
    x=4-3
\end{equation}
Hence, $x$ must be 1:
\begin{equation}
    x=1 
\end{equation}
Some comments on the conclusion
\end{compactequations}

\end{document}