The game starts as follows. You pick one medal without unwrapping it, and then the game host unwraps one of the remaining medals
and reveals that it is a silver medal. (Assume here that the host unwraps a medal with equal probability, but knowing where the gold medal was and avoiding unwrapping the gold medal if still on the table, to keep the game interesting to watch until the end.) You have now three medals left to unwrap (one in your hand, two on the table). At this point, the host gives you the option to change your mind and swap your medal for one of the two left on the table. What would you do at this point? Would you keep your medal, or swap it with one of the two medals left on the table? If so, which one?
The coefficient is the number just to the left of the variable. So that's why -8 is the coefficient for -8x. This is the variable term while 15 is the constant (it has no variable multiplied with it). The two terms are 15 and -8x since we can write 15-8x as 15+(-8x). Terms are separated by a plus sign.
