8. Please show your work

The 2000 census in a particular area gives us an age distribution that is approximately given (in millions) by the function f(x) = 39.8 + 2.1x - 0.744x2 where x varies from 0 to 9 decades. The population of a given age group can be found by integrating this function over the interval for that age group. a. Find the integral over the interval [0,9]. (Round to the nearest integer as needed.)