## anonymous one year ago What is the sum of a 7-term geometric series if the first term is −11, the last term is −171,875, and the common ratio is −5? −143,231 −36,047 144,177 716,144

the formula for the sum of a geometric series is $\sum_{i=0}^n a\ r^i=a \frac{1-r^{n+1}}{1-r}$ where a is the first term, r is the common ratio, and in your case, n is 6