find the Equivalence classes of this equivalence relation

Question

Is this correct?

Let R and S be the equivalence relations on Z X Z defined by

((a,b),(c,d)) ∈ R if and only if ab=cd

and ((a,b),(c,d)) ∈ S if and only if ad=bc

Find the equivalence class $[(3,4)]_R$

$[(3,4)]_R$= {cd=12,c and d in Z}