We have found that focusing on the solutions is often the best way to parametise a question so we are going to replace the 4 and 7 with the parameters $p and $q.
HINT: We can give the parameters whatever names we like and we could have, instead, replaced the 11 and 28. This is just the easiest option!
When we push the $p button in FX Equation, we are given the option to create and edit some parameters.
We have just used simple range parameters for $p and $q but we already have 49 possible variations!
HINT: Parameters are defined one per line.
We won't worry about the other parts of this screen yet. For the moment, just remember that we have $p and $q, each of which can range between 3 and 9. Let's push OK and move on to the next step.