Question

Multimea {x€N|127 mai mic sau egal decat 2*×+1 mai mic sau egal decat 721} contine 301 elemente . Adevarat sau fals? Dau coroanaaa

Answer 1

$M=\left \{ x\:\in\:\mathbb{N}\:|\:127 \leqslant 2x+1 \leqslant 721\right \}$

$cardM = 301 \: (?)$

$127 \leqslant 2x + 1 \leqslant 721 \: | - 1$

$126 \leqslant 2x \leqslant 720 \: | \div 2$

$63 \leqslant x \leqslant 360$

$x \: \in \: \mathbb{N} = > cardM=360 - 63 + 1 = 298$

$= > cardM = 298$