Need help in this please

A psychologist contends that the number of facts of a certain type that are remembered after t hours is given by the following function. 87t f(t) = 99t - 87 Find the rate of change at which the number of facts remembered is changing after 1 hour and after 10 hours. The rate of change after 1 hour is about facts / hour. (Round to the nearest integer as needed.) The rate of change after 10 hours is about facts / hour. K (Round to the nearest integer as needed.)