## Algebra: A Combined Approach (4th Edition)

$f^{-1} (x) = x+6$
$f (x) = x-6$ Step 1: Replace $f (x)$ with $y$. $$y = x-6$$ Step 2: Interchange $x$ with $y$. $$x = y-6$$ Step 3: Solve for $y$. $$y = x+6$$ Step 4: Replace $y$ with $f^{-1} (x)$. $$f^{-1} (x) = x+6$$