The function provided is:

$f(x) = -x^2 - 8x + 8$

We are asked to find $f(-5)$.

To do this, we substitute $x = -5$ into the function:

$f(-5) = -(-5)^2 - 8(-5) + 8$

First, calculate each term:

1. $(-5)^2 = 25$
2. $-(-5)^2 = -25$
3. $-8(-5) = 40$

Now, substitute the values:

$f(-5) = -25 + 40 + 8 = 23$

Thus, $f(-5) = 23$.

Would you like more details or further clarification?

Here are 5 related questions for practice:

1. Find $f(2)$ for the same function $f(x) = -x^2 - 8x + 8$.
2. What is the vertex of the parabola defined by $f(x) = -x^2 - 8x + 8$?
3. Determine the x-intercepts of $f(x) = -x^2 - 8x + 8$.
4. How would you rewrite $f(x) = -x^2 - 8x + 8$ in vertex form?
5. What is the axis of symmetry for the function $f(x) = -x^2 - 8x + 8$?

Tip: When evaluating functions, always double-check your substitutions for accuracy!