Do you need two expressions or one expression?
If it was one expression for both Denise and Stacy, it would look like this:
12 + 14c + 5g (12 = total amount in dollars of admission fee, 14c = total number of rides ridden, and 5g = total number of games played)
A single expression for Stacey would be:
6 + 7c + 3g
A single expression for Denise would be:
6 + 7c + 2g
Hope this helps!