McDonaldland is a fictional place used in marketing for McDonalds where Ronald McDonald and all of his friends live. As well as being used in advertising, the characters were used as the basis for equipment in the playgrounds attached to some McDonald's.
... the element 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 ...