9514 1404 393
Answer:
-177146
Step-by-step explanation:
The given formula is useful. The first term is a1 = -2. The common ratio is r = -6/-2 = 3. For n = 11 terms, the sum is ...
S11 = -2(1 -3^11)/(1 -3) = -2(-177146/-2) = -177146
The sum of 11 terms of the series is -177146.