Ok so y is going to mean the total amount of money. 15x means he gets 15 dollars for every week. And the x is weeks. The 35 shows that he starts with 35 dollars
So here is an example
Let’s say he has worked for 2 weeks- he would say y=15 (2)+ 35. Which you would do at times 2 which is 30 and then add that to 35. So he would have 65 dollars from working two weeks. Let me know if you need any,ore help