Multibit failure detection or correction methods exist, for example Chipkill[?] Correct.
Links http://www.dell.com/us/en/gen/topics/vectors_2000-chipkill.htm
... a being non-zero. These solutions are also called the roots of the equation. The formula reads <math> x=\frac{-b \pm \sqrt {b^2-4ac}}{2a} </math> Th ...