over too ey ?

I know I’ve asked about memorising formulas before, but I came across my notes from Diag Drill #3 and found a parabola question where I used x=-b/2a. Am I mistaken here ? Whats the pwn stance one this formula.

You don’t need to memorize that formula, but it sounds like you already know it. If you already know it, and you see an opportunity to use it, of course that’s fine. I guess a good exercise for you, though, would be to try to figure out how you might be able to solve that same question without that formula.