Răspuns:
-1 <= ( 2x + 1 ) : 3 < 3 / ×3
-1 × 3 <= 2x + 1 < 3 × 3
-3 <= 2x + 1 < 9 / -1
-3 -1 <= 2x < 9 -1
-4 <= 2x < 8 / :2
-4 : 2 <= x < 8 : 2
-2 <= x < 4
x apartine [-2 , 4 )
