4 y - 25
y^4 - 25
/ ___\ / ___\ / ___\ / ___\ \x + \/ 5 /*\x - \/ 5 /*\x + I*\/ 5 /*\x - I*\/ 5 /
(((x + sqrt(5))*(x - sqrt(5)))*(x + i*sqrt(5)))*(x - i*sqrt(5))
-25.0 + y^4
/ 2\ / 2\ \-5 + y /*\5 + y /
(-5 + y^2)*(5 + y^2)