I need help with these three questions and also if there is a formula can you tell me what it is. Thank You I need help because I don't understand this.

What is the missing constant term in the perfect square that starts with x^2 -20x

What kind of bond pays interest which is exempt from tax?

Ian is in training for a national hot dog eating contest on the 4th of july. on his first day of training, he eats 4 hot dogs. each day, he plans to eat 110% of the number of hot dogs he ate the previous day. write an explicit formula that could be used to find the number of hot dogs ian will eat on any particular day.