Need to find all real solutions to (x^2-1)^2-(x^2-1)-2=0

Question

Need to find all real solutions to (x^2-1)^2-(x^2-1)-2=0

Answer 1

3 real solution

0, -sqr2 and sqr2

no imaginary

it's 4th degree so 4 roots, but the 0 repeats. It has multiplicity 2