Bloody Sunday was an event that occurred in Selma, Alabama on March 7, 1965 in which Alabama State troopers and local law enforcement forcefully broke-up a group of 600 civil rights marchers. The event was televised and the apparent brutality of the images helped sway the opinion of the American people in favor of the US civil rights movement.
... formula is not ideal. See Loss of significance for details.
Derivation
The quadratic formula is derived by the method of completing the square[?]. ...