Australia
Belgium
Canada
China, mainland (People's Republic of China)
Chile
Denmark
England
Estonia
Finland
France
Germany
Guatemala
Honduras
Hong Kong
Ireland
Israel
Italy (listing taken from http://sito.cineca.it/strutture/struttura)
Japan
Netherlands
New Zealand
Norway
Northern Ireland
The Philippines
Poland
Portugal
Scotland
Singapore
Slovenia
South Africa
Spain
Sweden
Switzerland
United States of America
Wales
International
... b/(2a) from both sides, we get <math>x=\frac{-b}{2a}\pm\frac{\sqrt{b^2-4ac}}{2a}=\frac{-b\pm\sqrt{b^2-4ac}}{2a}.</math> ...