Question

6. Scrieți ca intervale următoarele mulțimi: a)A= {xe R|x>5}; c) C = {xe R | 3x ≤ 10}; b)B= {x= R |x-2}.​

Answer 1

Explicație pas cu pas:

$A = \Big\{x \Big| x \in \mathbb{R} \ , x > 5\Big\}$

$x \in \Big(5 ; +\infty \Big)$

$B = \Big\{x \Big| x \in \mathbb{R} \ , x<3\Big\}$

$x \in \Big(-\infty ; 3\Big)$

$C = \Big\{x \Big| x \in \mathbb{R} \ , 3x \leqslant 10\Big\}$

$3x \leqslant 10 \implies x \leqslant \frac{10}{3}$

$x \in \Big(-\infty ; \frac{10}{3} \Big]$

$D = \Big\{x \Big| x \in \mathbb{R} \ , 2x-7 > -2\Big\}$

$2x-7 > -2 \iff 2x > 5 \\ \implies x >\frac{5}{2}$

$x \in \Big(\frac{5}{2} ; +\infty \Big)$