text: it`s given that z,x and y are three prime numbers and z=xł-ył.find the value of x,y and z.?   you've got me... by definition they would have to be positive integers.  so the absolute value of -y, would just be y...  if they are all prime, how can you represent z as the product of two other primes?  that contradicts your assertion that they are all primes.  the only way to make this work is to allow 1 to be considered a 'prime' number, but with current definitions of prime, this is not the case, nor can 0 be considered prime...  or if these are supposed to be the difference of factorials, there's another problem.  every factorial of a prime (2! or above), will have 2 as a factor.  when you subtract two even numbers, the result is always even.  so the only way be if x! and y! were within 2 of each other.  using the smallest primes possible (3! and 2!) you have 6 - 2 = 4, which is not 2.  please explain what i'm missing...