Factor the polynomial function over the complex numbers. f (x) = x4+3x2-4

Insert a number into f (x) so f (x) = 0.

After trial and error I got * = - 1 giving one factor of (x + 1).

You can use the binomial division to get the other factors (divide your equation by (*+1).

I did this to get x^3-x^2+4x.