Hello, I was watching the last video of the AMC 10,12 lesson, and i realized that some of the questions were solved using methods that I could not relate to from previous lessons. I feel like the speed of the problem solving was too quick and needed some extra help on questions 2 and 6 of chapter 13. If you see this message, please help me with these questions as I find it hard to understand the methods that were used to solve them. Also, I am sending this message on the last available day to watch the lectures, and was wondering if the reply would be not available to be seen as it is my last day. If so, please email the response to dongseop.yeo@gmail.com as I am just trying to further understand. Thank you for your time.

Hello, I saw the reply but my computer is unable to open the file you posted, so could you please post in a different format?