Consider the following sequence. Sn = (-3) + 1 (a) Find the first three terms of the sequence whose nth term is given. $1 = 9 $2 = -27 S3=81 (b) Classify the sequence as arithmetic, geometric, both, or neither. O arithmetic O geometric O both neither x If arithmetic, give d; if geometric, give r; if both, give d followed by r. (If both, enter your answers as a comma-separated list. If neither, enter NONE x