Question

Resolva, em R, as equações
|x 3|
|9 3x|= 0

Answer 1

$\left|\begin{array}{ccc}x&3&\\9&3x&\end{array}\right|=0$

$D=\ x*3x-(3*9) = 0$

$3x^2-27=0$

$x^2= \frac{27}{3}$

$x^2= 9$

$x=3$
$x=-3$

S={-3,3}