[tex]6 {x}^{2} - 2 = 13[/tex]
You add both sides by 2
[tex]6 {x}^{2} = 15[/tex]
[tex] \frac{ {6x}^{2} }{6} = \frac{15}{6} [/tex]
[tex] {x}^{2} = \frac{15}{6} [/tex]
[tex] \sqrt{ {x}^{2} } = \sqrt{ \frac{15}{6} } [/tex]
[tex]x = \sqrt{ \frac{15}{6} } [/tex]