Question 909201
Be consistent with the variables. Z is not the same as z
z^4+2z^3+0*z^2+20z+12=0
It has no integer zeros
(z^2-2z+6) (z^2+4z+2) = 0
It has two real z = sqrt(2)-2, z = -sqrt(2)-2 and
 two complex solutions z = 1+i sqrt(5),  z = 1-i sqrt(5)