Question

What is the sum of a seven-term geometric series if the first term is -2, the last term is
-31,250, and the common ratio is -5?

Answer 1

Answer:

-26042

Step-by-step explanation:

sum of a finite geometric series =

$\frac{a_1(1-r^n)}{1-r}$

here, a1 is the first term, r is the common ratio, and n is the number of terms

a1 = -2

r = -5

n = 7

$\frac{a_1(1-r^n)}{1-r} = \frac{-2(1-(-5)^7)}{1-(-5)} = -26042$