Question

Daca A= { x apartie lui N / 5 supra x-4 apartine lui N } aflati multimea A

Answer 1

X∈N
$\frac{5}{X-4}$∈N
=> X-4>0=>

X-4=5 => X₁=9
X-4=1=> X₂=5
A={5;9}