How can I mix LaTeX in with Markdown? [closed]

Have you tried with Pandoc?

EDIT:

Although the documentation has become a bit complex, pandoc has supported inline LaTeX and LaTeX templates for 10 years.

Documents like the following one can be written in Markdown:

---
title: Just say hello!
author: My Friend
header-includes: |
    \usepackage{tikz,pgfplots}
    \usepackage{fancyhdr}
    \pagestyle{fancy}
    \fancyhead[CO,CE]{This is fancy}
    \fancyfoot[CO,CE]{So is this}
    \fancyfoot[LE,RO]{\thepage}
abstract: This is a pandoc test with Markdown + inline LaTeX
---

Just say hello!
===============

This could be a good example or inlined \LaTeX:

\begin{tikzpicture}
\begin{axis}
\addplot[color=red]{exp(x)};
\end{axis}
\end{tikzpicture}
%Here ends the furst plot
\hskip 5pt
%Here begins the 3d plot
\begin{tikzpicture}
\begin{axis}
\addplot3[
    surf,
]
{exp(-x^2-y^2)*x};
\end{axis}
\end{tikzpicture}

And now, just a few words to terminate:

> Goodbye folks!

Which can be converted to LaTeX using commands like this: pandoc -s -i Hello.md -o Hello.tex

Following is an image of the converted Hello.md to Hello.pdf file using MiKTeX as LaTeX processor with the command: pandoc -s -i Hello.md -o Hello.pdf

Finally, there are some open source LaTeX templates like this one: https://github.com/Wandmalfarbe/pandoc-latex-template, that can be used for better formatting.

As always, the reader should dig deeper if he has less trivial use cases than presented here.