You are standing still in a vacuum, and you throw a ball that moves 10 m/s away from you. Now you start moving in one direction at 5 m/s, and throw the ball in the other direction, away from the direction you are moving. The ball, relative to you, is going 10 m/s, but relative to an unmoving body, it is traveling 5 m/s.
My question is: is this same concept applied to light? If a light source is traveling away from you at a speed greater than that of light, would you be unable to see it? Or would light just keep going the same speed relative to an unmoving body?