Respuesta :
x^4 + 3x^2 - 4 = 0
(x^2 - 1))(x^2 + 4) = 0
x^2 - 1 = 0 giving x = 1 and x = -1
x^2 + 4 = 0 giving x^2 = -4 so x = +2i and -2i.
(x^2 - 1))(x^2 + 4) = 0
x^2 - 1 = 0 giving x = 1 and x = -1
x^2 + 4 = 0 giving x^2 = -4 so x = +2i and -2i.