Use the formula for the sum of the first n terms of a geometric sequence to solve. Find the sum of the first 8 terms of the geometric sequence: -8, -16, -32, -64, -128,

Respuesta :

Answer:

-2040

Step-by-step explanation:

[tex]S_n=a_1\dfrac{r^n-1}{r-1} \qquad\text{for first term $a_1$ and common ratio r}\\\\S_8=-8\dfrac{2^8-1}{2-1}=-2040[/tex]

The sum of the first 8 terms is -2040.