Answer:
Intervals A and C only
Step-by-step explanation:
we know that
The graph show a vertical parabola open upward
The vertex represent a minimum
The vertex is the point (-6,-9)
Remember that the vertex is a turning point
That means
In the interval (-∞,-6) the function is decreasing (rate of change is negative)
In the interval (-6,∞) the function is increasing (rate of change is positive)
therefore
<u><em>Verify each case</em></u>
Interval A) A -13 ≤ x ≤ -10
Belong to the decreasing interval, so the rate of change is negative
Interval B) -5 ≤ x ≤ 0
Find the rate of change
the average rate of change is equal to
In this problem we have
Substitute
![\frac{9-0}{0+5}=9/5](https://tex.z-dn.net/?f=%5Cfrac%7B9-0%7D%7B0%2B5%7D%3D9%2F5)
so
Interval B the rate of change is positive
Interval C) --10 ≤ x ≤ -2
Find the rate of change
the average rate of change is equal to
In this problem we have
Substitute
![\frac{-5+5}{-2+10}=0](https://tex.z-dn.net/?f=%5Cfrac%7B-5%2B5%7D%7B-2%2B10%7D%3D0)
so
Interval C the rate of change is zero
therefore
Intervals A and C only