Answer:
The series converges to -1.5.
Explanation:
This is a geometric series, so it converges if the number in parenthesis is between -1 and 1.
-1 < -3/5 < 1, so the series converges by the geometric series test.
Now we can plug this into the calculator (on TI-84, it's Math->0 summation) to find that the sum is -1.5. You can use 100 or another big number as a placeholder for infinity.