Answer:
B) x - 5
Step-by-step explanation:
The remainder theorem states the given a polynomial f(x), if f(x) is divided by x - a, the remainder will be f(a). Therefore, one needs to verify if f(a) = 0 in order to confirm it to be a factor of f(x).
a) x + 5:
f(a) = f(-5) = (-5)³ + 12(-5)² + 47(-5) + 60 = 0
b) x - 5:
f(a) = f(5) = (5)³ + 12(5)² + 47(5) + 60 = 720
c) x + 4:
f(a) = f(-4) = (-4)³ + 12(4)² + 47(4) + 60 = 0
d) x + 3:
f(a) = f(-3) = (-3)³ + 12(-3)² + 47(-3) + 60 = 0
One can observe that only the item B has f(a) not equaling 0, and thus it cannot be a factor of f(x).
