Answer:
3 + 9 + 27 + ...
Step-by-step explanation:
3 + 9 + 15 + ... is not a geometric series because it has no common ratio.
[tex]\frac{15}{9}\ne \frac{9}{3}[/tex]
3 + 9 + 27 + ... is a geometric series because there is a common ratio;
[tex]r=\frac{27}{9}=\frac{9}{3}=3[/tex]
3, 9, 27, ... is a geometric sequence and not a series. The sum of all the terms in a geometric sequence forms a geometric series.
3, 9, 15, ... is a not a geometric series.
