SOLUTION: Use summation notation to write the series 2.2+8.8+15.4+... for 5 terms.

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Question 853286: Use summation notation to write the series 2.2+8.8+15.4+... for 5 terms.
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
2.2+8.8+15.4+...

8.8-2.2 = 6.6
15.4-8.8 = 6.6

d = 6.6
a1 = 2.2

nth term = a1+(n-1)d = 2.2+(n-1)(6.6) = 2.2+6.6n-6.6 = 6.6n-4.4

sum%28%286.6n-4.4%29%2Cn=1%2C5%29

That's probably as far as you were expected to take it, but
it can be simplified as

sum%28%286.6n%29%2Cn=1%2C5%29%2Bsum%28%28-4.4%29%2C1%2C5%29%22%22=%22%226.6sum%28%28n%29%2Cn=1%2C5%29-4.4sum%281%2C1%2C5%29%22%22=%22%226.6sum%28%28n%29%2Cn=1%2C5%29-4.4%285%29%22%22=%22%226.6sum%28%28n%29%2Cn=1%2C5%29-22

Edwin