Answer:

Step-by-step explanation:
Given

Required
To determine if it is an exponential function, we have to write in form of

If we're able to do so, then the function is an exponential function.
If otherwise, then it is not

Apply Law of indices

Express 5^3 as 125

Factorize the exponent of 5

Express 5^2 as 25

This can be rewritten as:

By comparing the above to 
We have that


Since, we've be able to express the function as 
Then,
is an exponential function
the first few bars are the people who walked fewer than 4,000, so add up the numbers on the side (2 and 5) and you get 7, so a
I hope it’s right?! You just need to do this