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## Answers

I think it's 153. 9 + 11 |+ 13 + 15 + 17 + 19 + 21 +23 + 25 = 153

The formula can be used in bigger sets of numbers, that is, using the formula you can add even the given sequence is more than 100 items/terms.

x = {x / x is an odd number between 8 and 26}

x = {9, 11, 13, 15, 17, 19, 21, 23, 25}

n = 9 (number of items in the sequence or term)

d = 2 (common difference between any two consecutive term)

a₁ = 9 (the first term in the sequence)

a₉ = 25 (the 9th and last term in the sequence)

Sum of the series formula:

[2(a₁) + (n-1)(d)]

S₉ = 9/2 [2(9) + (9-1)(2)]

S₉ = 9/2 [ 18 + (8)(2)]

S₉ = 9/2 [18 + 16]

S₉ = 9/2 (34)

S₉ = 9 (17)

**S₉ = 153**

ANSWER: S₉

ANSWER: S

**= 153**