BEFORE YOU BUY!
TRY TO BORROW FIRST!!!
Go to your school library or local library and try to find a physical or digital copy and just borrow that. Textbooks are expensive for most people and are usually a waste of money unless you can afford to just straight up buy one without any issues.
Maths in Focus Mathematics Advanced Year 11 and Year 12 (Personally don't like the questions in this one but use it if you have to)
Cambridge Mathematics Advanced Year 11 and Year 12
New Senior Mathematics Mathematics Advanced Year 11 and Year 12
Terry Lee New Essential Mathematics and Terry Lee New Fundamental Mathematics
https://www.advancedmathematics.com.au/products.htm
Khan Academy