No!
No.
15 is relatively prime.
Two numbers are considered relatively prime if their GCF is 1. 4 and 9 are relatively prime.
Yes, they are.
Yes, they are relatively prime.
Yes, they are relatively prime.
Yes, they are relatively prime.
15 is not a prime number, so it can't be a prime factor.
No, 12 and 15 aren't relatively prime, because they both share as a prime factor 3. Dividing both12 and 15 by 3 gives 4 and 5 respectively. Consecutive numbers are always coprime. Coprime numbers are relatively prime to each other, as they share no prime factors, for example 33 and 35,
No, they are not relatively prime.
13 and 4 are relatively prime.
Yes, they are relatively prime.
No!
No.
No.
Yes, 4 and 21 are relatively prime. Numbers that are relatively prime only have the number 1 as a common factor. That is the case with 4 and 21.