Question

Factor the expression over the complex numbers x^2+20

Answer 1

`(x - 2i√(5) )(x+2i√(5) )`

Explanation:

To do that you need to use this:

`x^(2) -y^(2) =(x-y)(x+y)`

In order to do the substraction you need to put a minus to 20

`x^(2)+20 \\=x^(2) - (-20) \\=(x-√(-20) )(x+√(-20) ) \\=(x - 2i√(5) )(x+2i√(5) ); \\\\\\√(-20) =\sqrt{(-1)(2^(2))(5)} =2i√(5)`