2 z + 4*z + 1
z^2 + 4*z + 1
2 1 + z + 4*z
1 + z^2 + 4*z
/ ___\ / ___\ \x + 2 + \/ 3 /*\x + 2 - \/ 3 /
(x + 2 + sqrt(3))*(x + 2 - sqrt(3))
1.0 + z^2 + 4.0*z
1 + z*(4 + z)