[tex]\bf a.\\ \\ \it \dfrac{x+3}{7} < 1 \Rightarrow x+3 < 7\Big|_{-3} \Rightarrow x < 4 \Rightarrow x\in\{0,\ 1,\ 2,\ 3\}\\ \\ \\ \bf b.\\ \\ \it \dfrac{6}{x+4} > \dfrac{6}{8} \Rightarrow \dfrac{x+4}{6} < \dfrac{8}{6} \Rightarrow x+4 < 8|_{-4} \Rightarrow x < 4 \Rightarrow x\in\{0,\ 1,\ 2,\ 3\}[/tex]
