Find the sum of the geometric sequence - 3, 15, - 75, 375, ... when there are 9 terms and select the correct answer below.

Choices:

A. - 976,563

B. 976,563

C. 1,464,843

D. 976,562

Sn=sum of the n terms of the geometric sequence.

a = the first term

r=the common ratio

n=numbers of terms.

Sn=a[ (1-r^n) / (1-r) ]

In this case:

a=-3

r=a₂/a₁=15/-3=-5

n=9

S₉=-3[ (1 - (-5) ⁹) / (1 - (-5)) =

S₉=-3 (1+1953125) / 6) =

S₉=-3 (1953126/6) =

S₉=-3 (325521)

S₉=-976563

Answer: A. - 976563