In Roman folklore, Mezentius was an Etruscan King and father of Lausus[?]. He was sent into exile becaue of his cruelty, and he moved to Latium. He aided King Turnus against Aeneas and was killed in battle.
... because it discriminates between three qualitatively different cases:
If the discriminant is zero, then there is a repeated solution x, and this solution is real. ...