2 Questions: Answers with how to use formulas would be greatly appreciated to assist my learning. Thank You!

1. Determine the monthly payment on a loan for 800k, (assuming after a down payment) if the interest rate is 4% with a term of 30 years.

2. Decide that can afford to pay at most $616 a month. The dealership loan is offering 5 year payment plan compounded monthly, with an annual interest rate of 3.4%. What is the most expensive car can afford assuming no down payment? In other words, give the max loan balance that can afford at $616 per month.