Question

If f(x) = 5x, what is f–1(x)?

Answer 1

It would be 1/5x so C

Answer 2

Answer:

Correct option is:

$f^{-1}(x)=\dfrac{x}{5}$

Step-by-step explanation:

Let f(x)=y

Then, $f^{-1}(y)=x$

Hence, Value of x in terms of y gives the value of $f^{-1}(x)$

f(x)=y

i.e. 5x=y

i.e. x=y/5

Hence, $f^{-1}(y)=\dfrac{y}{5}$

Replacing y by x, we get

$f^{-1}(x)=\dfrac{x}{5}$

Hence, correct option is:

$f^{-1}(x)=\dfrac{x}{5}$