N = {set of natural numbers}
R = {(3, 8), (6, 6), (9, 4), (12, 2)}
(i) (3, 3) ∉ R ⇒ R is not reflexive
2a + 3b = 3
3b = 30 – 2a
b = (30 - 2a)/3
(ii) (3, 8) ∈ R (8, 3) ∉ R
⇒ R is not symmetric
(iii) (a, b) (b, c) ∉ R ⇒ R is transitive
(iv) ∴ It is not equivalence relation