Answer:
[tex]x = - 2 \sqrt{3} \: or \: x = 2 \sqrt{3} [/tex]
Step-by-step explanation:
The given equation is
[tex] {x}^{2} + 4 - 16 = 0[/tex]
Simplify to obtain:
[tex] {x}^{2} - 12 = 0[/tex]
Add 12 to both sides;
[tex] {x}^{2} = 12[/tex]
Take square root:
[tex]x = \pm \sqrt{12} [/tex]
[tex]x = \pm2 \sqrt{3} [/tex]
[tex]x = - 2 \sqrt{3} \: or \: x = 2 \sqrt{3} [/tex]
