Question

Find them sum of the first three terms of the geometric series represented by the formula9(-2)n-1.

Answer 1

Answer:

27

Step-by-step explanation:

The first three terms are :

$9(-2)^{1-1} =9*(-2)^{0} =9\\9(-2)^{2-1} =9*(-2)^{1} =-18\\9(-2)^{3-1} =9*(-2)^{2} =36$

The sum of these terms is

9+(-18)+36=27