## Precalculus (6th Edition) Blitzer

$19530$
The general formula to find the sum of a finite geometric sequence is given as: $S_{n}=\dfrac{a_1(1-r^n)}{1-r}$ Here, $a_1=5$ and $r=5$ Plug $n=6$ $S_{n}=\dfrac{a_1(1-r^n)}{1-r}$ Now, $S_{5}=\dfrac{5 \times [1-(5)^6]}{1-5}=19530$