Question

F(x)=x 3−9xf, left parenthesis, x, right parenthesis, equals, x, cubed, minus, 9, x What is the average rate of change of f over the interval [2,6] open bracket, 12, comma, 6, close bracket?

Answer 1

Answer:

$A(x) = 243$

Step-by-step explanation:

Given

$f(x) = x^3 - 9x$

$Interval: (12,6)$

Required

Determine the average rate of change

Average rate is calculated as thus;

$A(x) = \frac{f(b) - f(a)}{b - a}$

In this case; b = 12 and a = 6

Calculating f(12)

$f(12) = 12^3 - 9 * 12$

$f(12) = 1728 - 108$

$f(12) = 1620$

Calculating f(6)

$f(6) = 6^3 - 9 * 6$

$f(6) = 216 - 54$

$f(6) = 162$

Substitute 12 for b and 6 for a in $A(x) = \frac{f(b) - f(a)}{b - a}$

$A(x) = \frac{f(12) - f(6)}{12 - 6}$

Substitute values for f(6) and f(12)

$A(x) = \frac{1620 - 162}{12 - 6}$

$A(x) = \frac{1458}{ 6}$

$A(x) = 243$