PRACTICE EXERCISES

1. If n = 2x + 3 where x is an integer, then is n² - 1 divisible by 4?
   
   
   
2. Is 6 a factor of 141x * 4y?
   
   
   
3. Suppose x, y and z are integers such that x divides y and y divides z. Does x divides z? (In this case, we are proving the theorem of the transitivity of divisibility.)