Answer:
[tex]\large\boxed{x=-\sqrt{\sqrt{13}-4}}\ \vee\ x=\sqrt{\sqrt{13}-4}}[/tex]
Step-by-step explanation:
[tex]x^2+4=\sqrt{13}\qquad\text{subtract 4 from both sides}\\\\x^2+4-4=\sqrt{13}-4\\\\x^2=\sqrt{13}-4\Rightarrow x=-\sqrt{\sqrt{13}-4}}\ \vee\ x=\sqrt{\sqrt{13}-4}[/tex]
