Final answer:
To evaluate the function f(x) = 5x + 7 at x = 8, substitute 8 into the equation to get f(8) = 5(8) + 7, which simplifies to f(8) = 47. Hence, the answer is D. 47.
Step-by-step explanation:
To find f(8) given f(x) = 5x + 7, we simply substitute x with 8 in the equation and perform the calculation:
f(8) = 5(8) + 7
f(8) = 40 + 7
f(8) = 47
Therefore, the correct answer is D. 47. This process is known as Function Evaluation, which involves finding the output of a function given a specific input.