The 8 ball
If the black 8 ball is the object ball and a foul occurs during the shot, the game is over. This foul is loss of game.
depends on the game, most common are 8-ball in which there are 15.one player plays1-7, the other plays 9-15,then the 8. the other is 9-ball in which there 9. In 9 ball pool you hit the nine ball in last.10 or 16. The three most common pool games are 8 Ball, 9 Ball and Straight Pool. Both 8 Ball and Straight Pool use 15 numbered balls and the cue ball. In 9 Ball, only the first 9 numbered balls are used plus the cue ball.
8
That is lose of game.
This depends on the specific rules of the game you play. Under BCA and APA Rules the other player gets ball-in-hand.
Pool
The fifth ball in a pool ball triangle will dpend upon the game being played. In Straight Pool, it can be any of 13 different balls. Only the 1 and the 5 cannot be located there. In 8 Ball, the 5th ball must be the 8 ball.
you need to play the game :
Unless you are supposed to be aiming for the 8 ball, pocketing the 8 ball at any point in the game results in loss.
All pool games require that certain balls be identified. If you chose to use a custom set of pool balls with only the markings necessary for a particular game, it would not be contrary to the regulations to do so.
There are 8 coloured balls in a standard game of pool (the 1 through 7 and the 8 ball), and there are 7 striped balls. That sums to 15 balls.