Im assuming we are in a commutative setting here.
Reflexive ?
Symmetry
Think you can do transitive?
(2,3), so the things equivalent are of the form and must satisfy , so the equivalence class is
In other words (a, b) is in the same equivalence class as (2, 3) if and only if . You could think of that class as all fractions that are equivalent to the fraction and so representing the rational number .