Here is example of a page with LaTeX formulas (how it appears in WordPress editor):
 in the
 in the  (
 ( is odd) equidistant points around
 is odd) equidistant points around  :
:
      ![Rendered by QuickLaTeX.com \[ f_k = f(x_k),\: x_k = x^*+kh,\: k=-\frac{N-1}{2},\dots,\frac{N-1}{2} \]](https://eframath.com/wp-content/ql-cache/quicklatex.com-f619c040f841df035c83b77990402b44_l3.png)
where  is some step.
 is some step.
Then we interpolate points  by polynomial
 by polynomial
 (1)    
Its coefficients  are found as a solution of system of linear equations:
 are found as a solution of system of linear equations:
 (2)    
Here are references to existing equations: (1), (2).
Here is reference to non-existing equation (??).
Same page processed by QuickLaTeX and published (how visitors see it in a browser):

For the display environments, equation numbering is automatic, but this may be overridden and the number set explicitly with \tag{..} placed within the display expression.
A number of options may be set for an expression with attribute tags such as size, color, background, align, as arguments of \quicklatex{} placed within the expression:
      ![Rendered by QuickLaTeX.com \[ \boxed{f(x)=\int_1^{\infty}\frac{1}{x^2}\,\mathrm{d}x=1} \]](https://eframath.com/wp-content/ql-cache/quicklatex.com-8d5393b62aa94e4ed1a24d7c95f75321_l3.png)
renders with green font of 25 pixels height:

Compilation of an expression may be suppressed, showing instead the LaTeX source, by preceding the expression with a !.
For mathematical graphs you may use tikzpicture and pgfplots, e.g. :

compiles to

see on-line tikz help for examples and more information.
Whether or not QuickLaTeX has been activated with , you may always place a LaTeX expression within  shortcodes everywhere on the site. Attribute tags are allowed:
 shortcodes everywhere on the site. Attribute tags are allowed:  .
.
Visit QuickLaTeX’s home page for more information on features, examples, tips & tricks, tikZ graphics inclusion, etc.