1.3.A.1Concept
For a linear function, the average rate of change over any length input-value interval is constant.
ExampleThree intervals, one rate1 / 4
Let f(x) = 3x − 5. Find the average rate of change of f over [0, 2], [1, 5], and [−4, 10]. What do you notice?
Try it on paper first, then reveal each step to check your work.
Step 1 — Use the rate formula each time
Average rate of change over [a, b] = (f(b) − f(a)) / (b − a).