Question

Urgent please help with finding rate of change

Answer 1

When working with functions (of all types), the average rate of change is expressed using function notation:

$\dfrac{f(b)-f(a)}{b-a}.$

For the interval from x=7 to x=8,

1. find f(7) and f(8):

• $f(7)=729\cdot 3=2187;$
• $f(8)=2187\cdot 3=6561;$

2. use given formula:

$\dfrac{f(8)-f(7)}{8-7}=\dfrac{6561-2187}{8-7}=4374.$

Answer: the average rate of change for the interval from x=7 to x=8 is 4374.