Question

2x ao quadrado -7= 1
qual valor de x?

Answer 1

$2x^{2}-7=1$
$2x^{2}=7+1$
$x^{2}=\frac{8}{2}$
$x=\sqrt{4}$
$x=2$

Answer 2

.
$2 x^{2} -7=1 \\ \\ 2 x^{2} =1+7 \\ \\ 2 x^{2} =8 \\ \\ x^{2} =8\div2 \\ \\ x^{2} =4 \\ \\ x=\pm \sqrt{4} \\ \\ x=\pm2 \\ \\ S=\{-2,+2\}$