# How do you find the complex roots of #x^4-10x^2+9=0#?

##### 1 Answer

Jan 10, 2017

The roots are

#### Explanation:

Note that

Hence we find:

#0 = x^4-10x^2+9#

#color(white)(0) = (x^2-9)(x^2-1)#

#color(white)(0) = (x^2-3^2)(x^2-1^2)#

#color(white)(0) = (x-3)(x+3)(x-1)(x+1)#

So the four roots of this quartic equation are

These are Real numbers, but any Real number is also a Complex number (of the form