Question

varog ajutatima repede​

Answer 1

Salut!

A={ x ∈ ℕ* | 15/ 4×-3 ∈ ℕ}.

ℕ*- mulțimea numerelor numerelor naturale mai mari decât 0.

x ∈ { 1, 2}.

Numerele sunt:

$\frac{15}{4 \times 1 - 3} = \frac{15}{1} = 15.$

$\frac{15}{4 \times 2 - 3} = \frac{15}{5} ^{(5} = 3.$

Answer 2

$\it \dfrac{15}{4x-3}\in \mathbb{N} \Rightarrow 4x-3|{15} \Rightarrow 4x-3\in\{1,\ 3,\ 5, \ 15\}|_{+3} \Rightarrow 4x\in\{4,\ 6,\ 8,\ 18\}\ \ \ \ (1)\\ \\ x\in\mathbb{N}^*\ \ \ \ \ (2)\\ \\ (1),\ (2) \Rightarrow 4x\in\{4,\ \ 8\}|_{:4} \Rightarrow x\in\{1,\ \ 2\}$