Answer:
y = 13x
Step-by-step explanation:
If "y" represents how much he earns total
and "x" represents the number of games sold
then the equation is 
which can be simplified to 
Step-by-step explanation:
(f-g)(x)=

<span>79.99/6.75%=5.399325 if you want the exact but 5.40 if you want rounded</span>
I'm not at my desk and can't check it out right now.
But I think you should try 10 and -42 .