SOLUTION: find the sum of the first 20 terms of the sequence defined by an=5n+4

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Question 865875: find the sum of the first 20 terms of the sequence defined by an=5n+4
Answer by richwmiller(17219) About Me  (Show Source):
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an=5n+4
a1=9
a2=14
a3=19
S = ½(18 + (19)5)20
S = 1130
d=5
an = 9 + 5(n - 1)