Question

. ajutați-mă va rog ​

Answer 1

Răspuns:

Explicație pas cu pas:

$\frac{0}{11} \in Z^{\star} \Longrightarrow fals \: pt \: ca \: \frac{0}{11} = 0 \: ; \: 0 \notin Z^{\star}$

$\frac{2}{7} \notin Z \Longrightarrow adevarat \: pt \: ca \: \frac{2}{7} \in Q$

$- 9 \notin Z \Longrightarrow fals$

$\frac{20}{5} \in Z \Longrightarrow adevarat \: pt \: ca \: \frac{20}{5} = 4 \: ; \: 4 \in Z$

Answer 2

Răspuns:

Explicație pas cu pas:

$\frac{0}{11}\in\mathbb{Z}^{*}\Rightarrow 0\in\mathbb{Z}^{*}\Rightarrow\bold{F (fals)}\\\\ \frac{2}{7}\notin\mathbb{Z}\Rightarrow \bold{A(adev\u{a}rat)}\\\\-9\notin\mathbb{Z}\Rightarrow\bold{F(fals)}\\\\\frac{20}{5}\in\mathbb{Z}\Rightarrow 4\in\mathbb{Z}\Rightarrow \bold{A(adev\u{a}rat)}$

Reține!

1. $\mathbb{Z}=\mathbb{Z_{-}}+\{0\}+\mathbb{Z_{+}}$;
2. $\mathbb{Z_{-}}=\{-a|\:a\in\mathbb{N}^{*}\}$;
3. $\mathbb{Z_{+}}=\mathbb{N}$;
4. $\mathbb{Z}^{*}=\mathbb{Z} - \{0\}$.