Answer:
The sum of the first 5 terms is -244
Step-by-step explanation:
To calculate the sum of the geometric series, we need the first term, the common ratio and the number of terms we would like to sum.
The first term here is -4
The common ratio is T2/T1 or T3/T2 = 12/-4 = -3
number of terms n = 5
The formula to use is;
Sn = a(1-r^n)/(1-r)
Plugging these values, we have;
Sn = -4(1-(-3)^5)/(1-(-3))
Sn = -4(1+243)/4 = -1(244) = -244
