This is a list of the world's ship operating companies listed alphabetically by continent and country. This list includes companies both operating now and in the past.
... we get
<math>x=\frac{-b}{2a}\pm\frac{\sqrt{b^2-4ac}}{2a}=\frac{-b\pm\sqrt{b^2-4ac}}{2a}.</math>
Generalizations
The formula and its proof remain ...