Question

What is the sum of the geometric sequence –4, 24, –144, … if there are 7 terms?

Answer 1

coomon ratio = 24 / -4 = -6
use
a * (r^n - 1)
-------
r - 1

where n = 7, r = -6 and a = -4

Answer 2

this is the one i needed help on :)

Answer 3

wait would the answer be positive or negative?

Answer 4

i got -159964

Answer 5

better chech that - i rushed it - answer will be negative

Answer 6

Thank you so much! I will double check :) thanks!!