In Quiz - How to give validation to the Short - Answer Text Box

Hi,

I created a Quiz. I have used only "Short answer questions".
I installed Field validation,Richform,Clientside validation modules from Drupal.
I want to validate if the user types apart from some Texts.

Example:
I want the user to type only x,y,z,+,* characters and symbols nothing else. If the user type some other characters or symbols means the quiz have to throw a message.

Note: These kind of validation done in edX course.
When i took a course i noted this.