Question

Find the sum of the first seven terms of the geometric series 8, −24, 72, …

4,376
4,280
5,832
5,836

Answer 1

4376

Explanation:

8, −24, 72, -216, 648, -1944, 5832

Multiply the next number by -3

8 x -3 = -24

-24 x -3 = 72

72 x -3 = -216

-216 x -3 = 648

648 x -3 = -1944

-1944 x -3 = 5832

adding all 7 numbers

8 + (−24)+72 + (-216)+648+ (-1944)+5832 = 4376