R1={(a,b)∈N×N:∣a−b∣≤13} andR2={(a,b)∈N×N:∣a−b∣=13}In R1:∵∣2−11∣=9≤13∴(2,11)∈R1 and (11,19)∈R1 but (2,19)∈/R1∴R1 is not transitiveHence R1 is not equivalenceIn R2:(13,3)∈R2 and (3,26)∈R2 but (13,26)∈/R2(∵∣13−26∣=13)∴R2 is not transitiveHence R2 is not equivalence.