Answer:
Gah! Inverses!
Step-by-step explanation:
This is a pretty simple concept, just switch the x and f(x) values!
If you don't understand, look at how I solve it!

Switching the positions of the x and f(x) values...

Note: That f(x)^-1 is the proper notation for inverse functions.

There you go!
Hope this helps, and don't procrastinate!
5. Because 5 x 5 = 25. 25 x 5 = 125. or 5^3 is 125, which could be proved with a calculator. Hope this helps.
C. More of the children were close to 12 years old than 6 years old.