Find f(g(x)) f(x)=x+6 g(x)=x-6

$f (x) = x + 6$ $g (x) = x - 6$

Set up the composite result function.

$f (g (x))$

Evaluate $f (x - 6)$ by substituting in the value of $g$ into $f$ .

$f (x - 6) = (x - 6) + 6$

Combine the opposite terms in $(x - 6) + 6$ .

Add $- 6$ and $6$ .

$f (x - 6) = x + 0$

Add $x$ and $0$ .

$f (x - 6) = x$