To compare the average rates of change of the exponential function and the quadratic function \( f(x) = x^2 - 20 \) over the interval \([-9, 2]\), we need to calculate the average rate of change for each function over that interval.
-
Quadratic Function \( f(x) = x^2 - 20 \):
- Calculate \( f(-9) \) and \( f(2) \): \[ f(-9) = (-9)^2 - 20 = 81 - 20 = 61 \] \[ f(2) = (2)^2 - 20 = 4 - 20 = -16 \]
- The average rate of change from \(-9\) to \(2\) for \( f(x) \): \[ \text{Average rate of change} = \frac{f(2) - f(-9)}{2 - (-9)} = \frac{-16 - 61}{2 + 9} = \frac{-77}{11} = -7 \]
-
Exponential Function:
- Let's assume the points given \((-9, -1)\) and \((2, 15)\) correspond to the exponential function \(g(x)\).
- The average rate of change from \(-9\) to \(2\) for the exponential function: \[ \text{Average rate of change} = \frac{g(2) - g(-9)}{2 - (-9)} = \frac{15 - (-1)}{2 + 9} = \frac{16}{11} \approx 1.45 \]
Now, with both average rates of change calculated:
- The estimated average rate of change of \( g(x) \) (exponential) over the interval \([-9, 2]\) is approximately \( 1.45 \).
- The estimated average rate of change of \( f(x) \) (quadratic) over the interval \([-9, 2]\) is \( -7 \).
Comparison:
- The estimated average rate of change of the exponential function is positive, while the estimated average rate of change of the quadratic function is negative.
Therefore, the correct response is: "The estimated average rate of change of the exponential function over the interval \([-9,2]\) is negative, while the estimated average rate of change of \( f(x) \) over the interval \([-9,2]\) is positive."