SOLUTION: 7+-2+-11+-20+...+-119 given the following series, write each series using summation notation, using the nth term

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Question 974240: 7+-2+-11+-20+...+-119 given the following series, write each series using summation notation, using the nth term
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
7+-2+-11+-20+...+-119 given the following series, write each series using summation notation, using the nth term
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If n = 1 , 7
If n = 2 , 7-9 = -2
If n = 3 , 7-2*9 = -11
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Solve 7-9x = -119
-9x = -126
x = 14
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So, if n = 15, 7-14*9 = -119
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Ans: summation from n = 1 to 14 of (7-(n-1)9)
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Cheers,
Stan H.
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