Răspuns :
[tex]\it -3x\leq9|_{(-1)}\Rightarrow 3x\geq-9|_{:3} \Rightarrow x\geq-3\ \ \ \ \ \ (1) \\ \\ x\in \mathbb{Z} \ \ \ \ \ (2) \\ \\ (1), \ (2) \Rightarrow x\in\{-3,\ -2,\ -1,\ 0,\ 1,\ 2,\ 3, ...\}[/tex]
[tex]\it -3x\leq9|_{(-1)}\Rightarrow 3x\geq-9|_{:3} \Rightarrow x\geq-3\ \ \ \ \ \ (1) \\ \\ x\in \mathbb{Z} \ \ \ \ \ (2) \\ \\ (1), \ (2) \Rightarrow x\in\{-3,\ -2,\ -1,\ 0,\ 1,\ 2,\ 3, ...\}[/tex]