<span><em>Explanation:</em> </span> In order for it to be a geometric sequence, it has to be multiplied by the same number every time. The only equation that demonstrates this is the last one since it is being multiplied by 2 every time.
The geometric sequence equation is A(n) = a* r^{n-1} a( n ) = term in the sequence a = first term r = common ratio (what it's multiplied by every time)
Step by step explaination: Positive number = 5 When Exponent is 3, it equals: 125 When exponent is 0, it equals: 1 When exponent is -2, it equals: 1/25 or .04