For the function f(x)=(3x)/(x+2)
a. Find the average rate of change from x=2 to x=5
b. Find the derivative f'(x) from first principles, by setting up the difference quotient, (f(x+h)-f(x))/(h) and finding lim h->0 (f(x+h)-f(x))/(h)
c. Use part b to find the rate of change of f(x) at x=2