Q. Given the function f(x)=x2+9x+12, determine the average rate of change of the function over the interval −5≤x≤−1.Answer:
Identify average rate of change formula: Identify the average rate of change formula, which is (f(b)−f(a))/(b−a), where a and b are the endpoints of the interval.
Calculate f(−5): Calculate the value of f(−5) by substituting x=−5 into the function f(x)=x2+9x+12.f(−5)=(−5)2+9∗(−5)+12f(−5)=25−45+12f(−5)=−8
Calculate f(−1): Calculate the value of f(−1) by substituting x=−1 into the function f(x)=x2+9x+12. f(−1)=(−1)2+9∗(−1)+12 f(−1)=1−9+12 f(−1)=4
Use average rate of change formula: Use the average rate of change formula with f(−5)=−8 and f(−1)=4.Average rate of change = (f(−1)−f(−5))/(−1−(−5))Average rate of change = (4−(−8))/(−1+5)Average rate of change = (4+8)/4Average rate of change = 12/4Average rate of change = 3