Sets and Relations Part 1

Reflexive : (a,a)‌‌gcd of (a,a)=1
Which is not true for every a EZ.
Symmetric:
Take a=2,b=1‌‌gcd(2,1)=1
Also 2a=4≠b
Now when a=1,b=2‌‌gcd(1,2)=1
Also now 2a=2=b
Hence a=2b
⇒R is not Symmetric
Transitive:
Let a=14,b=19,c=21
gcd(a,b)=1
gcd(b,c)=1
gcd(a,c)=7
Hence not transitive
R is neither symmetric nor transitive.