Question

If $x^2-|x|-2=0$, then $x=$

• A. $\pm 2$
• B. $-1$
• C. $1$
• D. $2,1$

Answer 1

The correct option is A $\pm 2$

$x^2-|x|-2=0$
$\Rightarrow |x{|}^2-|x|-2=0$
$\Rightarrow (|x|-2)(|x|+1)=0$
$\Rightarrow |x|=2$
or $|x|=-1$ which is absurd.
$\therefore x=\pm 2$