A geometric sequence has a second term of 6:
The first term is the second term divided by the common ratio r.
The third term is the second term multiplied by the common ratio r.
and the sum of the first 3 term is -14
Clear the fraction by multiplying through by r
Divide through by 2
Arrange in descending order
Factor:
Use zero-factor property:
3r+1=0; r+3=0
3r=-1; r=-3
r=
So there will be two solutions to this problem.
Using r=, the sequence is
-18,6,-2,
Fourth term =
-------
Using r = -3, the sequence is
-2, 6, -18, 54
Fourth term = 54.
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Edwin
