Answer:
25/9
Step-by-step explanation:
25/9

The formula of the sum of a geometric sequence:

We have:

substitute:

Answer: C. -5460
You can set both fractions to have the same denominator by multiplying 6/8 (both the 6 and 8) by 2 to keep the value of the fraction, while turning the denominator to 16. So you get 12/16=y/16.
That means for the equation to be true y has to be 12.
Hope this helps!
Im pretty sure the answer is c) 136