Please help with *Excel formula*

"Assume the compounding period suggested by problem. Assume that payments are end of period payments."

4a. You need $455,000 to start a business 17 years from now. Your uncle has given you a gift of $145,000 today. Assuming you can earn 8% per year with annual compounding, will you have enough money to meet your goal? How much are you over/short? 4b. Your uncle has changed his mind and has revoked his gift. If you were to make annual contributions and could still earn an APR of 8% with annual compounding, how much will you need to contribute at the end of each year in order to meet your goal