Question

What is the average rate of change for this quadratic function for the intervalfrom x= -5 to x= -3?10-1810-10A. 80B. -8C. 16D.-16

Answer 1

The average rate of change can be found in the following way:

Identify the values of the function for the extremes of the interval. In this case, we need to find f(-5) and f(-3);

• Find the difference ,Δf = f(-3) - f(-5),;

• Find the difference ,Δx = -3 - (-5),;

• Calculate the average rate ,Δf/Δx,.

So, first, we see from the graph that:

f(-3) = 1

f(-5) = -15

Then, we have:

Δf = 1 - (-15) = 1 + 15 = 16

And:

Δx = -3 - (-5) = -3 + 5 = 2

Finally:

Δf/Δx = 16/2 = 8

Therefore, the average rate of change for this quadratic function for the given interval is

8 (option A)