When the letter “X” is in the middle of a word, it is pronounced in one of two ways.  It is pronounced as /KS/ or /GZ/.  Here is a rule to determine how to say “X” in a word.

If the “X” comes between two vowels say /GZ/.  If the “X” comes between a vowel and a consonant then say /KS/.  Here are some examples:

“X” pronounced /GZ/:  exit, exude, exam

“X” pronounced as /KS/:  extreme, extra, expert