Question

ajutor! am nevoie doar la 4,4 și 1. dau coroană!!!!!!​

Answer 1

Explicație pas cu pas:

4

a)

$|x + 3| \leqslant 2 \\ - 2 \leqslant x + 3 \leqslant 2 \\ - 2 - 3 \leqslant x \leqslant 2 - 3 \\ - 5 \leqslant x \leqslant - 1 \\ x \in \Big\{ - 5; - 4; - 3; - 2; - 1\Big\}$

b)

$|2x + 5| < 9 \\ - 9 < 2x + 5 < 9 \\ - 9 - 5 < 2x < 9 - 5 \\ - 14 < 2x < 4 \\ - 14 : 2 < x < 4 : 2 \\ - 7 < x < 2 \\ x \in \Big\{-6; -5; -4; -3; -2; -1; 0; 1\Big\}$

c)

$2[3 \cdot |2x - 7| - 7] - 23 < 17 \\ 2[3 \cdot |2x - 7| - 7] < 17 + 23 \\ 2[3 \cdot |2x - 7| - 7] < 40 \\ 3 \cdot |2x - 7| - 7 < 20 \\ 3 \cdot |2x - 7| < 20 + 7 \\ 3 \cdot |2x - 7| < 27 \\ |2x - 7| < 9 \\ - 9 < 2x - 7 < 9 \\ - 9 + 7 < 2x < 9 + 7 \\ - 2 < 2x < 16 \\ - 1 < x < 8 \\  x \in \Big\{ 0; 1; 2; 3; 4; 5; 6; 7\Big\}$