Question

A={x apartine IN | 8 supra x apartine IN}

Answer 1

A={x ∈ IN | 8 / x  ∈  IN}  ⇔ x ≤ 8;   divizibil cu 8 ⇒ x = 1; 2 ; 4  si  8

A = { 1;  2;  4;   8 }  x ∈ N ;  

8 / 1 = 8 ∈ N ;   8 / 2 = 4 ∈ N;  8 / 4 = 2 ∈ N;  8 / 8 = 1 ∈ N