Problem: Webwork 2.15, new installation, not displaying Math, the problem is Mathjax. Mathjax v3 is installed but not supported yet.
Solution (from installation instructions): Roll back MathJax to version 2
General information on MathJax including installation instructions can be found at http://www.mathjax.org/.
MathJax is already installed in the location /opt/webwork/MathJax and a link (called mathjax) to this directory is placed in /opt/webwork/webwork2/htdocs/ . However the new version MathJax v3 is a complete rewrite of MathJax from the ground up and its internal structure is quite different from that of version 2.
WeBWorK currently does not work with MathJax v3 so we have to switch to the legacy-v2 branch of MathJax.
Do the following:
$ cd /opt/webwork/MathJax/
$ git checkout legacy-v2