(9^-3)(9^12) Don't even answer if you won't explain how this works, I need help to figuring this out for multiple problems not just one, please explain in depth and not confusingly. Thanks sorry if this sounds rude

Idont understand math at all! : o( use this scenario to answer the remaining questions: brenton purchased a new bedroom set for $4,500.00. he lives in arizona and pays a 8.75% sales tax. if he made a 50% down payment and financed the rest, what amount did he finance? what is the total sales tax brenton will pay? enter your answer in currency format, round to the nearest cent. what was brenton's total amount financed? enter your answer in currency format, round to the nearest cent.