Question 185088
1- identify as arithmeic,geometric or neither
4,10,18,28,40
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2-write the rule for the nth term- 
a(n) = n^2 + 3n
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3-find a(1) = 1^2 + 3*1 = 1 + 3 = 4
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the answer is neither but whats the rest?
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Cheers,
Stan H.