Final answer:
The value of f(-6) is 12 when f(x) = -x + 6 and x = -6.
Step-by-step explanation:
When f(x) = -x + 6, and x = -6, the value of f(-6) can be found by substituting -6 into the given function and simplifying.
f(-6) = -(-6) + 6 = 6 + 6 = 12
Therefore, the value of f(-6) is 12.