Question

Va rog sa ma ajutati si pe mine dau coroana !

Scrieti elementele multimilor de mai jos.Ce observati
A={X ∈|N | 7 ≤egal ≤11 }
B={X ∈ |N | 5≤x-2≤9}
C=X ∈ |N |13≤2x-1≤21

Answer 1

A={7,8,9,10,11}
5≤x-2≤9|+2 => 7 ≤ x ≤ 11 => x ∈ {7,8,9,10,11} =>
=> B = {7,8,9,10,11}

13≤2x-1≤21|+1 => 14 ≤ 2x ≤ 22 | :2 => 7 ≤ x ≤ 11 => x ∈ {7,8,9,10,11} =>
=> C = {7,8,9,10,11}

Observam ca multimile sunt egale.
A=B=C

Answer 2

   
[tex]A=\{x \in N~ |~ 7 \leq x \leq 11 \} \\ \Longrightarrow ~A = \{7;~8;~9;~10;~11 \} \\ \\ B=\{x \in N~ |~ 5 \leq x-2 \leq 9 \} \\ 5+2 \leq x ~\Longrightarrow ~ 7 \leq x \\ x \leq 9+2 ~\Longrightarrow ~ x \leq 11 \\ \Longrightarrow ~ B= \{7;~8;~9;~10;~11 \} [/tex]


[tex]C=\{x \in N~ |~ 13 \leq 2x-1 \leq 21 \} \\ 13+1 \leq 2x ~\Longrightarrow ~ \frac{14}{2} \leq x ~\Longrightarrow ~7 \leq x \\ 2x \leq 21+1 ~\Longrightarrow ~x\leq\frac{22}{2} ~\Longrightarrow ~ x \leq 11 \\ \Longrightarrow ~ C= \{7;~8;~9;~10;~11 \} \\ \\ \Longrightarrow ~ A=B=C =\{7;~8;~9;~10;~11 \} [/tex]