Answer:
x=+/- root 5..................
[tex]2 {x}^{2} - 2 = 12 \\ 2 {x}^{2} = 12 + 2 \\2 {x}^{2} = 14 \\ {x}^{2} = \frac{14}{2} = 7 \\ {x}^{2} = 7 \\ x = \sqrt{7} \\ thank \: ou[/tex]
