Yeah, they provide you with a massive booklet, mostly with problems, but also a summary of the concepts - they're good for general revision and as a refresher of the whole course. Lectures might be a little rushed toward the end due to the time constraints, but they provide you with answers (including working out) for most of the questions so you can go through the rest yourself. The quality of explanation might depend on the lecturer though, as they do change from time to time, but generally they're quite experienced/have been doing this for a number of years, and are actual HSC markers, so they can give you exam tips (common mistakes, notes on working out, etc.) - if you know you're not going to spend those 7 hours hxc studying maths, I'd recommend going to the lectures