From what I am looking at, it seems as if it is. :)
Step-by-step explanation:
Area of circle

r = radius of the circle
Answer:
-4
Step-by-step explanation:
negative plus a negative means add
You add the number then keep the negative sign
The sum can be rewritten as y=4x, where y=f(x).
Now, we can rewrite the equation a x=y/4
Therefore, inv(f(x))=x/4