Question

ajutati maaa ex 2 ...​

Answer 1

Explicație pas cu pas:

$A = \Big\{x \Big|x \in \mathbb{N}, \ x = {n}^{2}, \ n \in \mathbb{N}\Big\}$

$B = \Big\{x \Big| x \in \mathbb{Q}, \ x = \frac{a}{a + 1}, \ a \in \mathbb{N^{\ast}} \Big\}$

$C = \Big\{x \Big| x \in \mathbb{Z}, \ x \in \mathcal{D}_{10}\Big\}$

$D = \Big\{x \Big| x \in \mathbb{N}, \ x \ \vdots \ 7\Big\}$

$E = \Big\{x \Big| x \in \mathbb{Z}, \ x \in \mathcal{D}_{1}\Big\}$