The answer is 15. It’s important to remember PEMDAS like always, remember that. So you’re going to just plug in your Y and your X, so you’ll have (3x5 - 3) + 3
Remembering to do multiplication in the parentheses first, you’ll get (15-3) + 3. Then you finish the parenthesis and get 12+3, and then you finish the problem getting 15.