Both numbers are composite because they have more than two factors
Yes, 11 and 51 are relatively prime.
They are not relatively prime. To be relatively prime, the only common factor they could have would be the number 1. Both also have the number 3 as a common factor, so they are not relatively prime.
Yes, they are relatively prime.
It can be. 50 is relatively prime to 51.
No.
No.
No.
No
Yes.
52
Yes.
31 is prime, but 51 is not as 51=3*17.