Răspuns :
[tex]\it a)\\ \\ 2x+1\ este\ divizor\ impar\ al\ lui\ 6\\ \\ (2x+1)|6 \Rightarrow 2x+1\in\{ -3,\ -1,\ 1,\ 3\}\bigg|_{-1} \Rightarrow 2x\in\{-4,\ -2,\ 0,\ 2\}\bigg|_{:2} \Rightarrow \\ \\ \Rightarrow x \in \{-2,\ -1,\ 0,\ 1 \}[/tex]
[tex]\it b)\ \ \overline{xy}+7y=10x+y+7y=10x+8y=2(5x+4y)=\ num\breve ar\ par[/tex]