SOLUTION: How do I find a1 for the geometric series Sn= 31.5 an= -4 r=-6?

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Question 1016837: How do I find a1 for the geometric series Sn= 31.5 an= -4 r=-6?

Answer by robertb(5830)   (Show Source): You can put this solution on YOUR website!
Use the formula .
After substitution, we get
.
Continue the steps to get the value of .

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