Assuming the series is

The series will converge if

We have

So the series will certainly converge if

, but we also need to check the endpoints of the interval.
If

, then the series is a scaled harmonic series, which we know diverges.
On the other hand, if

, by the alternating series test we can show that the series converges, since

and is strictly decreasing.
So, the interval of convergence for the series is

.
It’s either 40 or 5 games because it says that each team will play every other team once
For the second question, your first option is correct, you would rewrite 8 in power-base form 8=2^3 as the first step to solving the equation, power base form is exponential form.
Answer:
It was President Reagan’s support for anti-communist revolutions. It was used as an attempt to end the Cold War (geopolitical tension after world war ll)