Answer:
a. 
b. 
Step-by-step explanation:
First, we need tot find a general expression for the amount of caffeine remaining in the body after certain time. As the problem states that every hour x percent of caffeine leaves the body, we must substract that percentage from the initial quantity of caffeine, by each hour passing. That expression would be:

Then, to find the amount of caffeine metabolized per hour, we need to differentiate the previous equation. Following the differentiation rules we get:

The rate is negative as it represents the amount of caffeine leaving the body at certain time.
(2, 8) because 8 is not negative
hope it helps,
xXbeautyXx
Answer:
40 feet
Step-by-step explanation:
We are given a right isosceles triangle having lengths of two sides 12 feet and 16 feet.
<em>Since, the triangle is an isosceles triangle i.e. two sides of the triangle are equal.</em>
That is, the three sides of the triangle are 12 feet, 12 feet and 16 feet.
We know that, Perimeter of a triangle = Sum of the sides
Thus, Perimeter of the given triangle = 12 + 12 + 16 = 24 + 16 = 40 feet.
Hence, the total length of the fencing needed is 40 feet.