Once you have requested to enable this extension you can enter Latex math formatting enclosing it between two <math> and </math> tags. You obtain directly a latex equation environment that you should be familiar with.
For more info see the official mediawiki documentation
It is currently disabled due to lack of request. It is possible to enable it, however.
Keep in mind that this extension supports only a subset of latex commands. Most features are available, some advanced ones may not.
Below you can find some samples.