am nevoie de ajutor enumerati elementele multimilor

Răspuns:
E={ x∈ Z| -3|x si |2x-1| <19}
|2x-1| <19 => -19<2x-1<19 |+1 <=> -18<2x<20| :2 <=> -9<x<10
cum -3|x si x∈Z
=> x∈{-6;-3;0;3;6;9} = E
F={ x∈Z| 13/x+2 ∈ N}
13/x+2 ∈ N => x+2 |13 => x+2 ∈ D₁₃={1;13} |-2 => x∈{-1;11}=F