# What are the complex roots of the equation x^2-20?

May 20, 2018

If you meant ${x}^{2} = - 20$
then then $x = \pm 2 \sqrt{5} i$
$\sqrt{- 20} = \sqrt{20} i = \sqrt{{2}^{2} \cdot 5} i = 2 \sqrt{5} i$
${x}^{2} = - 20 \Rightarrow x = \pm \sqrt{- 20}$