To show set A={x∈Z:0≤ x ≤12},whose R={(a,b):a=b} is an equivalence? How? thanks!?

As I know only that all a in the set can only be equal to itself hence,R=reflexive.But don't know how the relation also satisfy symmetric and transitive. Thanks to answer!

let consider the two pair (a,b) and (b,c) belongs to R.
We knw that any pair like (a,b) then a=b as it is given as condition.

similarly (b,c)belongs to R so b=c

a=b and b=c so a must be equal to c.

that is a=c. so, for every a,b and b,c belongs to R , (a,c) must belongs two R hence its transitive.

let (a,b) belongs two R.
by property a=b
if a=b then b must be equal to a that is b=a .so, (b,a) belongs to R.
hence for every (a,b) belongs to R there exist (b,a) belongs to R. Hence,symmetric.

For any a belongs to z. (a,a) belongs to R as a=a . hence,reflecsive

Hence, its equivalence.