Average Rate of Change f(x)=1/x, interval [a,b]

[Hoodp]

The question is find the average rate of change of the function y=1/x given the interval [a,b].

If anyone could help me with this I would greatly appreciate it.

 

[HallsofIvy]

What is f(b)? What is f(a)? The total change, between x= a and x= b is f(b)- f(a). And the average change, per x, is that divided by the change in x: b- a.