SOLUTION: -78 is which term of an arithmetic sequence whose common difference is -4 and whose first term is 6?

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Question 244913: -78 is which term of an arithmetic sequence whose common difference is -4 and whose first term is 6?
Answer by stanbon(75887) About Me  (Show Source):
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-78 is which term of an arithmetic sequence whose common difference is -4 and whose first term is 6?
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a(n) = a(1) + (n-1)d
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-78 = 6 + (n-1)(-4)
-84 = (n-1)(-4)
n-1 = 21
n = 22
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The 22nd term is -78
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Cheers,
Stan H.