Question

Resolva as equações:
${ \times }^{2} = 99 - 10 { \times }^{2}$

Answer 1

$x^{2} =99-10^{2}$

$x^{2} +10x^{2} =99$

$11x^{2} =99$

$x=\sqrt{\frac{99}{11}} =\sqrt{9} =3$