[tex]\\ \sf\longmapsto -\sqrt{64}[/tex]
[tex]\\ \sf\longmapsto -\sqrt{8\times 8}[/tex]
[tex]\\ \sf\longmapsto -\sqrt{8^2}[/tex]
[tex]\\ \sf\longmapsto 8i[/tex]
It belongs to set of complex numbers
