If n is a natural number, then 6n^2 + 6n is always divisible by? Answers:
A) 6 only
B) 6 and 12
C) 12 only
D) 18 only
E) 20 only
6n^2 + 6n = 6n(n+1), which is always divisible by 6 and 12 both, since n(n+1) is always even.   Answer is 6 and 12
<result>B</result>
If n is a natural number, then 6n^2 + 6n is always divisible by?