Question

If f(x) = 5x, what is f^-1(x)?

Answer 1

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

Rearranging the formula of $f(x)=5x$: $f(x)=5x\to \frac{f(x)}{5}=x\to f^{-1}(x)=\frac{x}{5}=\frac{1}{5}x$

For all inverse functions, $f^{-1}(f(x))=x$. This can verify the answer by $f^{-1}(f(x))=\frac{1}{5}f(x)=\frac{1}{5}(5x)=x$

Answer 2

Answer:

Third choice

Step-by-step explanation:

They are asking us to find the inverse of y=5x. To do this you just switch x and y and then remake y the subject of the equation (solve for y.)

y=5x

x=5y (I switch x and y)

x/5=y ( I divided both sides by 5)

Then you just replace y with the f^-1(x) thing

f^-1(x)=x/5

or

f^-1(x)=1/5x