E aí, Marcos
Eu vou tentar desenvolver as contas com calma e se aparecer alguma dúvida você avisa aí.
Expandido [tex3]\left(\frac{C_{3}^{2n}}{C_{2}^{n}}\right) = \frac{44}{3}, \, [/tex3]
temos:
[tex3]{\large\frac{ \frac{2n!}{3!(2n-3)!}}{\frac{n!}{2!(n-2)!}}} = \frac{44}{3}[/tex3]
[tex3]\frac{2n!}{3!(2n-3)!} \, \cdot \, \frac{2!(n-2)!}{n!} = \frac{44}{3}[/tex3]
[tex3]\frac{2n(2n-1)(2n-2)\cancel{(2n-3)!}}{3!\cancel{(2n-3)!}} \, \cdot \, \frac{2!\cancel{(n-2)!}}{n(n-1)\cancel{(n-2)!}} = \frac{44}{3}[/tex3]
[tex3]\frac{2n(2n-1)(2n-2)}{3!} \, \cdot \, \frac{2!}{n(n-1)} = \frac{44}{3}[/tex3]
[tex3]\frac{2n(2n-1)2\cancel{(n-1)}}{3!} \, \cdot \, \frac{2!}{n\cancel{(n-1)}} = \frac{44}{3}[/tex3]
[tex3]\frac{2n(2n-1)2}{3!} \, \cdot \, \frac{2!}{n} = \frac{44}{3}[/tex3]
[tex3]3! \cdot n \cdot 44 = 2n(2n-1)2 \cdot 2! \cdot 3[/tex3]
[tex3]264n = 48n^2 - 24n \,\, \Rightarrow \,\, n(48n-288) = 0[/tex3]
[tex3]n = \frac{288}{48} = 6.[/tex3]