Final Answer:
The number that goes in the box is 8. Option C is answer.
Step-by-step explanation:
The function f(x) is defined as f(x) = 5x + 3. To determine the number that goes in the box, we need to evaluate the function at a specific value of x. The question doesn't provide a specific value for x, so we can choose any value and evaluate the function accordingly.
Let's evaluate f(x) at x = 1:
f(1) = 5 * 1 + 3
f(1) = 5 + 3
f(1) = 8
Therefore, the number that goes in the box is 8. The complete function is f(x) = 5x + 3.
Option C is answer.