Methylene Blue, methylthionine chloride or 3,7-bis(dimethylamino)phenothiazin-5-ium chloride is a chemical compound used as a dye and medication for Gram's stain, Wright stain[?], and the treatment of metoxyhemoglobinemia.
... the formula should be understood as "either of those element(s) of the field whose square equals b2 - 4ac". In some fields, some elements have no ...