Yeah, but pronouncing TeX "tek" is a bit of a shibboleth among mathematicians. The use of Greek letters is common enough in math papers to make it a natural inference (it's not an English "X", it's a capital Greek χ [0])—at least within the field. And if you don't know it, when one of your professors explains it to you you'll feel like they let you in on a little secret.

[0]: https://en.wikipedia.org/wiki/Chi_(letter)