$$A- \frac{ 1 }{ A } =0TOA+ \frac{ 1 }{ A }$$
$A=\sqrt{2}\approx 1.414213562$
$A=-\sqrt{2}\approx -1.414213562$
$O\in \mathrm{C}$
$A=-\sqrt{2}\text{ or }A=\sqrt{2}$
$O\in \mathrm{R}$
$|A|=\sqrt{2}$