No.
55 and 72 are relatively prime because they have no prime factors in common.
18 = 2 x 32 and 55 = 5 x 11 so yes it is.
Yes, 11 and 51 are relatively prime.
Yes, 55 and 62 are relatively prime because they have no common factor greater than 1.
Yes. 11 is prime. 98 is not prime, but it is not divisible by 11, so the two are relatively prime.
Yes
11 is a prime number. For it to be relatively prime, it needs to be compared to another integer.
Yes, they are relatively prime.
Yes, they are relatively prime.
11 and 110 are not relatively prime because they have 11 as a common factor.
Yes