Final answer:
To find the value of g(x) when x=4, substitute the value of x into the given equation g(x) = x^2 - 16, which results in g(4) = 16 - 16 = 0. Thus, the correct answer is A. 0.
Step-by-step explanation:
The student is asking for the value of the function g(x) when x = 4. Given that g(x) = x^2 - 16, we substitute 4 for x in the equation to find the value of g(4).
g(4) = (4)^2 - 16
g(4) = 16 - 16
g(4) = 0
Therefore, the answer is A. 0.