Question

A={x€|4 supra 2x-1 €N}​

Answer 1

Explicație pas cu pas:

Ti am atașat poza, succes

Answer 2

$\it x\in\mathbb{N} \Rightarrow 2x-1\ este\ num\breve ar\ impar\ \ \ \ \ (*)\\ \\ \dfrac{4}{2x-1}\in\mathbb{N} \Rightarrow 2x-1\Big |4\ \stackrel{(*)}{\Longrightarrow}\ 2x-1=1|_{+1}\Rightarrow 2x=2 \Rightarrow x=1$