Answer:
[tex]\large\boxed{x=3-\sqrt{14}\ \vee\ x=3+\sqrt{14}}[/tex]
Step-by-step explanation:
[tex]x^2-6x-5=0\qquad\text{add 5 to both sides}\\\\x^2-6x=5\\\\x^2-2(x)(3)=5\qquad\text{add}\ 3^2\ \text{to both sides}\\\\x^2-2(x)(3)+3^2=5+3^2\qquad\text{use}\ (a-b)^2=a^2-2ab+b^2\\\\(x-3)^2=5+9\\\\(x-3)^2=14\to x-3=\pm\sqrt{14}\qquad\text{add 3 to both sides}\\\\x=3-\sqrt{14}\ \vee\ x=3+\sqrt{14}[/tex]