Question

Determinati elementele urmatoarei multimi:

D={ x ∈ N $| \frac{4x+3}{5x-1}$ } ∈ N }

Answer 1

4x+3/5x-1∈N;
⇒4x+3=5x-1⇒5x=4x+3+1⇒5x=4x+4⇒x=4;
⇒16+3/20-1=19/19=1∈N⇒adevarat;
⇒D=[4];