SOLUTION: The seventh term is 56 and the 12th term is -1792 of the geometric progression. Find the ration and the first term. Assume the ratios are equal.

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Question 1119294: The seventh term is 56 and the 12th term is -1792 of the geometric progression. Find the ration and the first term. Assume the ratios are equal.
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
56%2Ar%5E%285%29=-1792
r%5E5=-1792%2F56=32
r%5E5=2%5E5
r=2-----but need r%3C0 so r=-2
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A%2A2%5E%287-1%29=56
A%2A2%5E6=7%2A2%2A2%2A2
A%2A2%5E3%2A2%5E3=7%2A2%5E3
A%2A2%5E3=7
A=7%2F8

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First Term, highlight%287%2F8%29
Ratio, highlight%28-2%29