x mũ 2 -13=0 giúp nha

`x^2 - 13 =0`

`⇔ x^2=13`

`⇔` \(\left[ \begin{array}{l}x = \sqrt{13}\\x = - \sqrt{13}\end{array} \right.\) 

Vậy ` x∈` { $\sqrt{13}$ ; - $\sqrt{13}$}