# How do you find the roots of #x^4-5x^2+4=0#?

##### 1 Answer

Mar 22, 2018

#### Explanation:

Let

#y^2 - 5y + 4 =0#

This is a nice and simple trinomial to factor.

#(y - 4)(y - 1) =0 #

#y = 4 or y = 1#

We now reverse our substitution.

#x^2 = 4 or x^2 =1#

#x = +- 2 or +-1#

The graph of the function

graph{x^4 - 5x^2 + 4 [-10, 10, -5, 5]}

Hopefully this helps!