The number of cases of a new infectious disease is doubling every year such that the number of cases is modeled by a sequence whose general term is an -75(2), where n is the number of the year just beginning. Find how many cases there will be at the beginning of the fourth year. Find how many cases there were at the beginning of the first year. At the beginning of the fourth year, the number of cases will be At the beginning of the first year, the number of cases was