Math Olympiad

Blah, I have always been excelling in Math as it has always been my pet subject, but this year, I'm taking Additional Math, or Advance Math. I'm pretty much struggling with it. We're in the third topic now, which is Quadratic Functions, and the first and second one is Fuctions and Quadratic Equations. I'm pretty much half-half in all three topics... And I was selected to represent my school in the National Math Olympiad, because of my previous year Math results, (one of which is 100... ) and I don't know what to do now... I'm pretty much okey in General Math, so well, I've been trying to study more, and attend tuition for Additional Math, and stuff... it's really tough... I just had my Add Math test today, and out of the 7 questions, I answered 4 and a half, while the rest I only managed to do halfway... I wonder if anyone can give me the simplest formula which I need to know for both functions and quadratic equations, something I can understand easier? My Add Math teacher is so un-understandable...