SOLUTION: Determine whether each series is arithmetic or geometric. Then find the sum to the given term. {{{35+70+140+280+"..."+S[7]}}}

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Question 303394: Determine whether each series is arithmetic or geometric. Then find the sum to the given term.
35%2B70%2B140%2B280%2B%22...%22%2BS%5B7%5D
Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
35%2B70%2B140%2B280%2B%22...%22%2BS%5B7%5D

It's geometric with r=2 because each term is 2 times the
preceding term:

S%5Bn%5D=a%5B1%5Dr%5E%28n-1%29

n=7, a%5B1%5D=35,  r=2

S%5B7%5D=35%282%29%5E%287-1%29

S%5B7%5D=35%282%29%5E6

S%5B7%5D=35%2864%29

S%5B7%5D=2240

Edwin