Question

f (x) = 6x + 4. Find the inverse of f(x).
O A. f-1 (2) = 4 - 6x
O B. f-1(x) = 6x - 4
O c. f-(x) =
O D. f-'(x) = 20
2-4
-6

Answer 1

If $f^{-1}(x)$ is the inverse of f(x), then

$f\left(f^{-1}(x)\right) = x$

By definition of f(x), we have

$f\left(f^{-1}(x)right) = 6f^{-1}(x) + 4 = x$

Solve for the inverse :

$6f^{-1}(x) + 4 = x$

$6f^{-1}(x) = x - 4$

$f^{-1}(x) = \dfrac{x-4}6$

which makes C the correct choice.