Answer:

f(x) = 4 when x is 8
Step-by-step explanation:
Domain is the set of x values that make the function defined. Allowed x values for the function (mapping).
The Range is the set of y values that make the function defined. Allowed y values for the function (mapping).
- Whenever we need to find f(a), suppose, then we look for "a" in the domain and see its corresponding value mapping in the range.
- Whenever we will be given a value for f(x) = a, suppose, and we have to find "x", we look at the value a in the range and find corresponding x value in the domain.
Firstly, we need f(4), so we look for "4" in domain and see which number it corresponds to in range.
That is 
Thus,

Next,
We want "x" value that gives us a "y" value of 4. We look for "4" in the range and see which value it corresponds to. That is "8". So,
f(8) = 4
Answer:
The two stadiums are approximately 3115.1 meters away from each other
Step-by-step explanation:
Since we can construct two right angle triangles between the blimp and the two stadiums as shown in the attached image, then the distance "x" between the two can be find as the difference between the right triangle legs that extend on the ground.
In order to find the size of such legs, one can use the tangent function of the given depression angles as shown below:

and for the other one:

The the distance between the stadiums is the difference:
b - a = 3405.7 - 290.6 meters = 3115.1 meters
There is one<span> last step after getting </span>x<span> = </span>3<span>. You must check </span>x<span> = </span>3<span> in the original equation to be sure that </span>x<span> = </span>3<span> does not cause a zero denominator.</span>