Hi,
MathML code bounded by \ ( and \ ) show delimiters.
Is this a question or a note?
If you use the MathJax filter of moodle 2.7 default configuration enables MathML but it does not check if the page has MathML and that way mathJax does not render MathML unless the page has some TeX with default TeX delimiters - see
MDL-43856 and MDL-44989
If you want to use MathML with current MathJax filter you can add to Site administration > Plugins > Filters > MathJax > Additional equation delimiters
<math
and MathJax will check if pages of moodle have MathML (otherwise only Mozilla browsers render MathML natively on pages)
Note also that moodle 2.7 is using HTML5 so you can use plain <math>...</math> tags for mathML: see https://developer.mozilla.org/en-US/docs/Web/MathML/Element/math
And finally because moodle does have a list of accepted html tags you can't use MathML tags everywhere in moodle - for example forum activity strips MathML tags (and other activities that students can edit... )
Delimiters \ ( ... \ ) are reserved for (La)TeX input in default MathJax configuration