[tex]\displaystyle\bf\\500:11=45~rest~5\\\implies~\textbf{Cel mai mic numar de forma }~\overline{5xy}~este:\\46\times11=\boxed{\bf506}\\600:11=54~rest~6\\\implies~\textbf{Cel mai mare numar de forma }~\overline{5xy}~este:\\54\times11=\boxed{\bf594}\\\textbf{Numerele sunt din 11 in 11.}\\ \textbf{incepand cu 506 pana la 594.}\\Acestea~sunt:\\506;~517;~528;~539;~550;~561;~572;~583;~594\\\textbf{Numarul de numere este:}\\\\n=\frac{594-506}{11}+1=\frac{88}{11}+1=8+1=\boxed{\bf9~numere}[/tex]