Question

determina nr nat x astfel incat 18 supra 2x+1 apartine N

Answer 1

$\it \dfrac{18}{2x+1} \in \mathbb{N} \Longrightarrow 2x+1 | 18 \Longrightarrow 2x+1\in D_{18} \Longrightarrow \\\;\\ \Longrightarrow 2x+1 \in \{1, 2, 3, 6, 9, 18\}|_{-1} \Longrightarrow 2x\in \{0, 1, 2, 5, 8, 17\}|_{:2} \\\;\\ \Longrightarrow \it x \in \{\it 0, 1, 4\}.$

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Answer 2

2x+1 este divizibil cu 18 ⇒2x+1∈ multimii divizorilor lui 18 ⇒2x+1∈{1,2,3,6,9,18} ⇒ 2x∈{0,1,2,5,8,17}⇒x∈{0,1,4}

Sper ca am fost de ajutor! :)