Inverse functions

Question

Hi, I need to know if my amswer is right because my book is saying something else. It says to find the inverse function of f(x)= x+5 . My answer for the inverse of this is f^-1 (x) = x-5

Answer 1

Hi Alex

Your answer is correct

f(x) = x+5, or y = x+5

To find the inverse, you need to solve for x

 

x = y-5, or x = f(x) - 5

 

The proper way to write it is f^-1(x) = x-5

 

(x+5) and (x-5) are symmetric around the origin, your answer is correct unless the book is different in notation or how the answer is written, can you post what the book specifically says?

 

The Khan Academy has a good video on this

https://www.khanacademy.org/math/algebra2/manipulating-functions/introduction-to-inverses-of-functions/v/introduction-to-function-inverses

 

 

Answer 2

f(x) = x + 5

x = f^-1(x) + 5

x - 5 = f^-1(x)

 

What does your book "say?"