Answer :
[tex]x^2+8=0\\
x^2=-8\\
x=-\sqrt{-8} \vee x=\sqrt{-8}\\
x=-\sqrt{8\cdot(-1)} \vee x=\sqrt{8\cdot(-1)}\\
x=-\sqrt{8}\cdot\sqrt{-1} \vee x=\sqrt{8}\cdot\sqrt{-1}\\
x=-\sqrt{4}\cdot \sqrt2\cdot i \vee x=\sqrt{4}\cdot \sqrt 2\cdot i\\
x=-2\sqrt{2}i \vee x=2\sqrt{2}i
[/tex]
