If x is a positive prime integer, can x + (composite number) ever equal a prime number? What about two composites added together, can they ever reach a prime number?

Question

mathmate · Answer

Examples:
17 (prime) + 6 (composite) = 23 (prime)
15(composite) + 14(composite) = 29 (prime)

mathmate · Answer

In fact, difference between two primes (other than 2) is always composite (div. by 2).

anonymous · Answer

Thank you. Could you help me on my other problem, it is about k^2 -18x +65. I asked it earlier. I'm stuck.

mathmate · Answer

You're welcome!  :)

Sorry, I was late for the other question. You already had an excellent response.