What are the solutions of 4x4 – 4x2 = 8?

To get the solution of this equation, we perform factoring first to simplify the equation:

4x4 – 4x2 = 8
4x2(x2-1)=8
x2(x2-1)=2

let x2=1 and (x2-1)=2 to satisfy the equation. Then,

x2=1
x = +1 and -1

x2-1=2
x2 = 2+1
x = +√3 and -√3

The 4 roots of the 4th-degree polynomial is -1, +1, +√3 and -√3.