Holy crap, MathML works here

[wrog]

It seems we can do shit like $a{x}^2+bx+c$ and maybe also $\frac{-b\pm \sqrt{b^2-4ac}}{2a}$. Wheee…

(And if this isn't looking right, you may need to switch/update your browser:  Google just released Chrome 109 which includes MathML support for the first time in a long while. Firefox has evidently had this since forever. Probably pointless waiting for Microsoft Edge to catch up (Update (2023-01-14):  Edge caught up). And Opera is owned by the Chinese now, so you probably shouldn't be using it anymore. Bleah.)

Looks like I get to go update my math-heavy posts.