SOLUTION: What is Sn of the geometric series with a1=-81, r=-2/3, and n=5? A)26 B) -39 C) -55 D)211

SOLUTION: What is Sn of the geometric series with a1=-81, r=-2/3, and n=5? A)26 B) -39 C) -55 D)211

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Question 855044: What is Sn of the geometric series with a1=-81, r=-2/3, and n=5?
A)26
B) -39
C) -55
D)211
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
S=a*(1 - r^n)/(1 - r)
S=-81*(1 - (-2/3)^5)/(1 - (-2/3))
S = -55
C) -55
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