Explicație pas cu pas:
a) -3 | x
[tex] |2x - 1| < 19 \\ - 19 < 2x - 1 < 19 \\ - 19 + 1 < 2x < 19 + 1 \\ - 18 < 2x < 20 \\ - 9 < x < 10[/tex]
=> E = {-6; -3; 3; 6; 9}
b) (x + 2) ∈ {-13; -1; 1; 13}
[tex]x + 2 = - 13 = > x = - 15 \\ x + 2 = - 1 = > x = - 3 \\ x + 2 = 1 = > x = - 1 \\ x + 2 = 13 = > x = 11[/tex]
=> F = {-15; -3; -1; 11}