Can someone please help

Let f be defined as shown.
What is f^-1 (-9)

Explanation:

The inverse undoes whatever f(x) does. So if the input is x = -8 leads to the output y = -9, then the inverse reverses the process. Effectively, the input and output swap. It's essentially asking the question "if f(x) = -9, then what is the value of x?". In this case, the answer would be x = -8

answer: a.   one is a factor of every whole number since every number is divisible by itself.