Need this answer quick due soon help

Which one ? is the answer and how to find this answer

Use composition to determine if (x) or h(x) is the inverse of f(x) for the limited domain x2-1.

Tomas used 3 1/3 cups of flour and now has 1 2/3cups left. which equation can he use to find f, the number of cups of flour he had to begin with? f+3 1/3=1 2/3 f-3 1/3=1 2/3 3 1/3f=1 2/3 f/3 1/3=1 2/3