## Precalculus (6th Edition) Blitzer

$5,15,45, 135, 405$
The general formula to find the nth term of a Geometric sequence is given as: $a_{n+1}=a_nr$ We are given that $a_1=5$ so, $a_2=a_1r = (5)(3)=15 ;\\ a_3=a_2r = (15)(3)=45; \\ a_4=a_3r = (45)(3)=135 ; \\ a_5=a_4r = (135)(3)=405$ Hence, the first five terms are: $5,15,45, 135, 405$