Answer:
[tex](x - 2i\sqrt{5} )(x+2i\sqrt{5} )[/tex]
Step-by-step explanation:
To do that you need to use this:
[tex]x^{2} -y^{2} =(x-y)(x+y)[/tex]
In order to do the substraction you need to put a minus to 20
[tex]x^{2}+20 \\=x^{2} - (-20) \\=(x-\sqrt{-20} )(x+\sqrt{-20} ) \\=(x - 2i\sqrt{5} )(x+2i\sqrt{5} ); \\\\\\\sqrt{-20} =\sqrt{(-1)(2^{2})(5)} =2i\sqrt{5}[/tex]
