For the first interval (-1, 2), f(-1) = f(2), which means that the average rate of change on that interval is zero, so the correct option is A.
<h3>
Over which interval the rate of change is zero?</h3>
For a function f(x) we define the average rate of change over the interval (a, b) is defined as:
R = (f(b) - f(a))/(b - a)
Here the function is:
f(x) = x^2 - x -1
And the rate of change will be zero on an interval (a, b) if and only if:
f(b) = f(a).
Notice that the first interval is (-1, 2)
f(-1) = (-1)^2 - (-1) - 1 = 1 + 1 - 1 = 1
f(2) = 2^2 - 2 - 1 = 4 - 2 - 1 =1
Then f(-1) = f(2), which means that the average rate of change on that interval is zero, so the correct option is A.
If you want to learn more about average rate of change:
brainly.com/question/23483858
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18 by 12
because 6*3=18 and then 4*3=12 so this is your answer
