I am really confused. I actually really like math puzzles but I couldn't understand what you were looking for, and couldn't find any relationship between 2, 8, and 7. I also don't understand how the 1 number we put in passes the information of both x and y.
So I tried to brute force it to see the next puzzles and it was the same puzzle but for some reason the answer was different. I am just really confused...
It looks really interesting but I can't figure out what I am supposed to figure out.
Oh, and by the way, when you get a puzzle wrong you are put back in the start of the entire thing, not just that puzzle.