Respuesta :

gmany

Answer:

[tex]\huge\boxed{S_8=3,280}[/tex]

Step-by-step explanation:

The formula:

[tex]S_n=\dfrac{a_1(1-r^n)}{1-r}[/tex]

Substitute:

[tex]n=8;\ r=3;\ a_1=1\\\\S_8=\dfrac{1\cdot(1-3^8)}{1-3}=\dfrac{1-6,561}{-2}=\dfrac{6,560}{2}=3,280[/tex]