Respuesta :

SvetlanaM

Answer: x = 2√3.

Step-by-step explanation:

[tex]x^{2} +6^{2} =(2x)^{2}\\\\x^{2} +36=4x^{2} \\\\4x^{2}-x^{2} -36=0\\\\3x^{2} -36=0\\\\3(x^{2} -12)=0\\\\x^{2} -12=0\\\\x^{2} =12\\\\x=\sqrt{12} =2\sqrt{3}[/tex]