Question

For the function f(x) = 5/x+4 find the average rate of change of f from 1 to x:

Answer 1

f(1) = 5/1 + 4 = 9
f(x) = 5/x + 4

avg rate of change from x=1 to x
= (5/x + 4 - 9)/(x-1)
= (5/x - 5)/(x-1)
= (5 - 5x)/(x(x-1))
= 5(1-x)/(x(x-1))
= -5/x

Answer 2

What is the average rate of change of the function f(x) on the interval -5≤x≤−4?