8)
[tex]\it4|\overline{41x}\Rightarrow 4|\overline{1x}\Rightarrow x\in\{2,\ 6\}\Rightarrow \overline{41x} \in\{412,\ 416\}\\ \\ 4|\overline{6x4}\Rightarrow 4|\overline{x4}\Rightarrow x\in\{2,\ 4,\ 6,\ 8\}\Rightarrow \overline{6x4} \in\{624,\ 644,\ 664,\ 684\}\\ \\ 4|\overline{7xx}\Rightarrow 4|\overline{xx}\Rightarrow x\in\{0,\ 4,\ 8\}\Rightarrow \overline{7xx} \in\{700,\ 744,\ 788\}[/tex]
