Question

If f(x) and f-1(x) are inverse functions of each other and F(x) = 2x + 5, what is f-1 (8)?

Answer 1

3/2

Explanation:

Find the inverse function of f(x) = 2x + 5:

1. Replace "f(x)" with "y:" y = 2x + 5

2. Interchange x and y: x = 2y + 5

3. Solve for y: 2y = x - 5, or y = (x - 5)/2

Then f^(-1)(8) = (8 - 5)/2, or 3/2