Respuesta :

Answer:

Answer is -759/5

Step-by-step explanation:

To find the sum of a finite geometric series, use the formula,  

Sn= a1-a1r^n/ 1-r

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

common ratio = a2/a1

S8=3-3(-2/3)8 / 1-(-2/3)

S8 = 3-(-2)8/ 1+ 2/3

S8= 3-256/ 3+2/3

S8= -253/5/3

S8= -253*3/5

S8= -759/5

Answer:

-19.7

Step-by-step explanation: