If you create Markdown Page and insert only inline math, MathJax does not render. You have to either add hidden "p" HTML tag with inline math or add some math in display style. It seems like Label and Quiz are also affected.

Steps to reproduce:

1. In user editor preferences set Plain text area
2. Create a page activity
3. In Page content are select Markdown format from dropdown menu
4. Enter this in content

   \\(x+y\\)

5. Save changes

Expected behavior: Formula is rendered as math formula
Actual behavior: plain text is displayed

1. Add extra line

   $$ssss$$

2. Save changes
3. Note that both formulas are rendered correctly as math formulas