Final answer:
To find the value of f(-5), substitute x = -5 into the given function f(x) = -x^2 - 8x + 8 and simplify.
Step-by-step explanation:
To find the value of f(-5) we need to substitute x = -5 into the given function f(x) = -x^2 - 8x + 8.
When we substitute -5 into the function, we get: f(-5) = -(-5)^2 - 8(-5) + 8.
Simplifying this expression gives us f(-5) = -25 + 40 + 8 = 23. Therefore, f(-5) = 23.