If f(x)=x+3 how do you find the inverse?

1 Answer
Nov 25, 2016

Please see the explanation.

Explanation:

Given: Find the inverse of f(x)=x+3

Substitute f1(x) for every x:

f(f1(x))=f1(x)+3

By definition, f(f1(x))=x:

x=f1(x)+3

Solve for f1(x)

f1(x)=x3

Check by verifying that f(f^-1(x)) = f^-1(f(x)) = x:

f(f1(x))=(x3)+3=x

f1(f(x))=(x+3)3=x

This checks.