Pressbooks supports LaTeX code, a typesetting language that is often used to format complex science and math equations.
You can enter LaTeX code in the Text version of the editor (not Visual) by putting
$latex before your LaTeX code. At the end of your LaTeX code, add a dollar sign ($) to tell Pressbooks that you are finished entering LaTeX code. Your LaTeX code should look like this:
This LaTeX code then gets converted to an image when viewed in a browser or exported to an ePub or PDF.