9. The average amount of soda consumed per person in the US from 1990 to 2010 can be modeled by the following equation, where x is the number of years since 1990. f(x) 5.852x^4-0.002x³ + 0.006x² + 0.029x + 47.855 Find the average rate of change for each time interval. a. 1990 to 1996 b. 1990 to 2000 c. 2005-2010​