[tex]x - 3 = 2 \cdot \sqrt{x} \\\\ \sqrt{x} = \frac{x-3}{2} \\\\ x = (\frac{x-3}{2})^2 \\\\ x = \frac{x^2 - 6x + 9}{4} \\\\ 4x = x^2 - 6x + 9 \\\\ x^2 - 10x + 9 = 0 \\\\ x = \frac{10 \pm \sqrt{100 - 4 \cdot 1 \cdot 9}}{2} \\\\ x = \frac{10 \pm 8}{2} \rightarrow \boxed{x' = 9 \ \text{e} \ x'' = 1}[/tex]
