What is speed x5 faster than light?

Answer 1

According to accepted physics theories, nothing can go _AT_ the speed of light.

It may be - it is probable! - that our "accepted physics theories" are incorrect in at least certain restricted cases. No one would be happier than I to learn that it were possible to go faster than light. But to the limits of our observational techniques, the theories have matched the realities of the experiments, and no way around them have been found - yet.

However, until a few fundamental physical laws are overturned, there really isn't any point in discussing what "speed 5x faster than light" might look like.