How do you find the common ratio for #7,14,28,56,128,...#?
For this sequence to have a common ratio, the ratio between any pair of consecutive terms must be the same.
So if this sequence does have a common ratio, then we can look at any pair of consecutive terms, e.g.
#14/7 = 2#
This ratio is the same for
I suspect a typo in the question. The value you would expect is