SOLUTION: Evaluate each series using sum formulas. 4 + 12 + 20 + 28 + …; n = 9 ie the sum of the 1st nine terms

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Question 849386: Evaluate each series using sum formulas.
4 + 12 + 20 + 28 + …; n = 9 ie the sum of the 1st nine terms

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

{4 + 12 + 20 + 28 +...}  Arithmetic Series  d = 8

S%5Bn%5D=%28n%2F2%29%282%2Aa%5B1%5D%2B+%28n-1%29d%29

S%5B9%5D=%289%2F2%29%282%2A4%2B+8%2A8%29= 324