A seaport is a major facility in a city, for the loading, unloading, and movement of cargo; to and from from oceanicships. The term also refers to a city with such a facility. (See also: port)
... 2a is zero and it is impossible to divide by it.)
The symbol
<math>\pm \sqrt {b^2-4ac}</math>
in the formula should be understood as "either of thos ...