THE ANSWER IS NOT IN THE LINK THAY THAT PERSON GAVE
3 and what?
if it is 3 and 5 than the answer would be 15
Answer:

Step-by-step explanation:
we know that
A relationship between two variables, x, and y, represent an inverse variation if it can be expressed in the form
or 
In this problem we have
For
-----> 
so
Find the value of k

substitute the value of x and f(x)


therefore
the equation is equal to

For
-------> substitute in the equation and find the value of f(x)

Remember that X will always be one up or down depending on if there is a - or not (if it is just an x) and one over! Hope this helps