pre calculus
posted by courtney .
find the average rate of change of
f(x)=x^35x+3:
a. from 6 to 3
b. from 1 to 2
c. from 2 to 8
I am so lost, can someone please show me how to do this?

I will do the first, you do the other two....
f(3) = 27 + 15 + 3 = 9
f(6) = 216 + 30 + 3 = 183
so avg rate of change = (9  (183))/(3(6))
= 174/3 = 58