I NEED HELP RIGHT NOW!!!! The picture is my question.

[tex]Answer: \\ \frac{x}{ \sqrt{ {(x + 6)}^{2} - {x}^{2} } } = \frac{ \sqrt{ {(x + 6)}^{2} - {x}^{2} } }{13} \\ \Leftrightarrow 13x = {(x + 6)}^{2} - {x}^{2} \\ \Leftrightarrow 13x = {x}^{2} + 12x + 36 - {x}^{2} \\ \Leftrightarrow x = 36[/tex]