During 18 weeks at the height of an influenza outbreak, the rate at which the number of cases of infection changed could be approximated by I'(t) = - 6.30t + 141.7, where I is the total number of infected people and t is time measured in weeks. Answer parts a) through d). . . . a) Estimate I(t), the total number of people who have contracted influenza by time t. Assume that I(0) = 1406. I(t) = - 3.1512 + 141.7t+1406 b) Approximately how many people contracted influenza during the first 8 weeks? people (Round to the nearest integer as needed.)