Question 1155804
-2i and +2i are roots, since complex roots are conjugate
-1 is other,
(x+1)
x=2i, x= -2i. (x^2+4)=0
(x+1)(x^2+4)
x^3+x^2+4x+4=0


also,
if first coefficient is 1 then 
x=(1/2)(-b+/- sqrt(b^2-4ac)
the discriminate is -16 and b is 0
therefore -4ac=-16
a is 1, c=4
(x^2+4)