Respuesta :

Answer:

x = 5  (Answer C)

Step-by-step explanation:

Set f(x) = 3x - 15 = to 0 and solve for x:

3x - 15 =  0

Adding 15 to both sides isolates 3x:

3x = 15

Dividing both sides by 3 yields x = 5  (Answer C)