The general formula for exponential growth and decays is:

if k>0 then then it is an exponential growth function. If k<0 then the function represents an exponential decay.
Now we need to classify each of the functions:
1.
The function

can be wrtten as:

comparing with the general formula we notice that k=2, therefore this is an exponential growth.
2.
The function

can be written as:

comparing with the general formula we notice that k=-4, therefore this is an exponential decay.
3.
The function

comparing with the general formula we notice that k=-1, therefore this is an exponential decay.
Answer:
x=5
Step-by-step explanation:
The equation of the rotating light is an illustration of a secant function
The equation that represents the distance between the center of the circle and the light source is 
<h3>How to determine the equation</h3>
The equation is a secant function represented by

Where:
A represents the amplitude
So, we have:
--- the distance of the light from each square wall
B represents the period, and it is calculated as:

The light completes its full rotation every 6 seconds.
This means that,
T = 6
So, we have:

Simplify

Substitute values for A and B in 

Rewrite as a function

Hence, the equation that represents the distance between the center of the circle and the light source is 
Read more about trigonometry functions at:
brainly.com/question/1143565