Thank you for contacting us Malick, our team is happy to answer any questions you have about working with Latex code in the Post and Page Builder!
I located a plugin called WP QuickLaTex in the public WordPress repository that seems like it should give you the functionality you are looking for on your website.
After activating the plugin I pasted the example code from their Getting Started page into one of my page sections and the formulas rendered with the expected formatting. Here is the example code I used:
[latexpage]
At first, we sample $f(x)$ in the $N$ ($N$ is odd) equidistant points around $x^*$:
\[
f_k = f(x_k),\: x_k = x^*+kh,\: k=-\frac{N-1}{2},\dots,\frac{N-1}{2}
\]
where $h$ is some step.
Then we interpolate points $\{(x_k,f_k)\}$ by polynomial
\begin{equation} \label{eq:poly}
P_{N-1}(x)=\sum_{j=0}^{N-1}{a_jx^j}
\end{equation}
Its coefficients $\{a_j\}$ are found as a solution of system of linear equations:
\begin{equation} \label{eq:sys}
\left\{ P_{N-1}(x_k) = f_k\right\},\quad k=-\frac{N-1}{2},\dots,\frac{N-1}{2}
\end{equation}
Here are references to existing equations: (\ref{eq:poly}), (\ref{eq:sys}).
Here is reference to non-existing equation (\ref{eq:unknown}).
This is how the formulas displayed on the frontend when previewing the page:
I hope that plugin helps you get your LaTex formulas working as expected and please let us know if there is anything else that we can do to help!