Respuesta :

x^4 - 3x^2 + 2 = 0
(x^2 - 2)(x^2 - 1) = 0

so either x^2 - 2 = 0  or x^2 - 1 = 0

so x^2 = 2 or x^2 = 1

so x = sqrt 2 , - sqrt2, 1 , -1   Answer

all the roots are real