Answer:
-25/7
Step-by-step explanation:
The sum of an infinite series with first term 'a' and common ratio 'r' is ...
S = a/(1 -r)
Your series has a=-5 and r=-2/5, so the sum is ...
S = (-5)/(1 -(-2/5)) = -5/(7/5) = -25/7
The sum of the series is -25/7.
