change site-scripts to
{{ $script := .Site.Data.webpack_assets.app }}
{{ with $script.js }}
<script src="{{ relURL (printf "%s%s" "dist/" .) }}"></script>
{{ end }}
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.7/MathJax.js?config=TeX-AMS-MML_HTMLorMML">
</script>
<script type="text/x-mathjax-config">
MathJax.Hub.Config({ tex2jax: {inlineMath: [["$$","$$"],["\\(","\\)"]]} })
</script>
and it works… AND changed single $ to double $$
Check .Site.Data.webpack_assets.app ! And better to use the newest MathJax version!
Good Luck!