Explicație pas cu pas:
e)
[tex] |2x - 1| < 19[/tex]
[tex] - 19 < 2x - 1 < 19 \\ - 18 < 2x < 20 \\ - 9 < x < 10[/tex]
-3 | x => E = {-6; -3; 0; 3; 6; 9}
f)
[tex] \frac{13}{x + 2}\in \mathbb{N} => (x + 2) \in \{1; 13 \} \\ [/tex]
[tex]x + 2 = 1 = > x = - 1[/tex]
[tex]x + 2 = 13 = > x = 11[/tex]
=> F = {-1; 11}
