The Royal Swedish Society of Sciences and Letters in Gothenburg or Kungl. Vetenskaps- och Vitterhetssamhället i Göteborg is one of the Royal Academies in Sweden. It was founded in the 1760s in Gothenburg, and given Royal Charter in 1778 by Gustav III of Sweden.
... it discriminates between three qualitatively different cases:
If the discriminant is zero, then there is a repeated solution x, and this solution is real. ...