Question

-64+4x ao quadrado = 0 ?

Answer 1

$-64+4x^2=0\to \\\\ 4 x^{2} =64\to \\\\ x^{2} = \frac{64}{4} \to \\\\ x^{2} =16\to x=\pm \sqrt{16} \to \\\\ x= \pm 4\\\\\\ S=(-4;4)$

Answer 2

Resolvendo a equação x=16
-64+4x^2=0
4x^2=0+64
4x^2/64=
x=16