Question

Resolva:
$5 + \sqrt{3x^{2} + 1 } = 12$

Answer 1

$5 + \sqrt{3x^{2} + 1 } = 12 \\ \\ \sqrt{3x {}^{2} } + 1 = 12 - 5 \\ \sqrt{3 {}^{2} } + 1 = 7 \\ 3x {}^{2} + 1 = 49 \\ 3x {}^{2} = 49 - 1 \\ 3x {}^{2} = 48 \\ x {}^{2} = 16 \\ x = 4 \: \: ou \: \: x = - 4$