/ ____________\ / ____________\ / ____________\ / ____________\ | / ____ | | / ____ | | / ____ | | / ____ | \x + I*\/ 4 - \/ 15 /*\x - I*\/ 4 - \/ 15 /*\x + I*\/ 4 + \/ 15 /*\x - I*\/ 4 + \/ 15 /
(((x + i*sqrt(4 - sqrt(15)))*(x - i*sqrt(4 - sqrt(15))))*(x + i*sqrt(4 + sqrt(15))))*(x - i*sqrt(4 + sqrt(15)))