Most of the time, the best way to create a regeneratable version of a question is to start with an existing question - something that is already "doing the job" that you want done. For this example we are going to use a simple trinomial factorisation question.
At the moment, this is a "static" question. We want to add parameters to the question so it can regenerate itself.
HINT: It is often best to start with the solution and work back to the question. We will be using this idea.