Question

Tell whether the sequence is arithmetic. If it is, what is the common difference?

-15, -9, -3, 3, ...

A) yes; 3
B) yes; 5
C) yes; 6********My answer
D) no

Answer 1

The answer to this is C.

Answer 2

The difference between -15 and -9 is 6 because you add 6 to -15 to get -9. The difference between -9 and -3 is also 6 because -9+6=-3. -3+6=3 also uses the number 6.
It is arithmetic because addition is applied.
You are correct. The answer is C.