The answer should be 664 in squared
The mean of the numbers is c. 67
They are essentially asking us to solve:

Solving this equation for x tells us that it will take around 80.1 years for the materials in the vault to reduce to 357 pounds.
Answer:
a. -5
b.-5
c.-5
Step-by-step explanation:
In order to find the average rate of change of a function , we divide the change in the output value by the change in the input value.
Generally, the average rate of change (ARC) on an ecuatios between two points (x1,f(x1)) and (x2,f(x2)) is
- ARC = [f(x2)-f(x1)]/ (x2-x1)
<em>In case a)</em>
f(-1)= -5*(-1)-8=5-8= -3 f(3)= -5*3-8= -23
Then ARC= (-23-(-3))/(3-(-1))=-20/4=-5
<em>In case b)</em>
f(a)= (-5a-8)
f(b)= (-5b-8)
Then ARC= [(-5b-8)-(-5a-8)]/(b-a)= (-5b+5a)/(b-a)= -5(b-a)/(b-a)= -5
<em>In case c)</em>
f(x)= -5x-8
f(x+h)= -5(x+h)-8= -5x-5h-8
then ARC= [(-5x-5h-8)-(-5x-8)]/(x+h-x) =-5h/h= -5