Question

Решите уравнения :
$1) \sqrt{x^{2} -16} =3\\\\2) \sqrt{3x^{2}+1 } =\sqrt{13}$

Answer 1

$1)x^2-16=3^2;\\\\x^2=25;\\\\x=\pm\sqrt{25};\\\\ x\pm5$

$2)3x^2+1=13;\\\\3x^2=12;\\\\x^2=4;\\\\x=\pm\sqrt{4};\\\\ x=\pm2$