Provide annotation with the similar format:

<math>
f(y) = sqrt(x+5)
</math>

Supporting the AsciiMath syntax:
[url=http://asciimath.org/" rel="noopener,nofollow]http://asciimath.org/[/url]

In the Fact View it already shows as a graphical formula.

Plain formulas are supported in a syntax similar to excel worksheet formulas. More documentation will follow.
(For PlantUML these are automatically reformatted to fit the AsciiMath syntax.)