To evaluate the function $g(x) = x + 8$ at $x = -9$, substitute $-9$ for $x$ in the function:

$g(-9) = -9 + 8$

$g(-9) = -1$

So, the answer in function notation is $g(-9) = -1$.

Would you like more details on this process or have any questions?

Here are 5 related questions:

1. What is $g(5)$ for the function $g(x) = x + 8$?
2. If $g(x) = x + 8$, what is $x$ when $g(x) = 0$?
3. How does the function $g(x) = x + 8$ shift the graph of $y = x$?
4. What is the inverse of the function $g(x) = x + 8$?
5. How do you determine the domain and range of the function $g(x) = x + 8$?

Tip: Remember that evaluating a function involves substituting the given value of $x$ into the function.