Source PostScript (solve2nddegre.pps)

%% syntaxe : a b c solve2nddegre --> x1 x2
/solve2nddegre {
5 dict begin
   /@c exch def
   /@b exch def
   /@a exch def
   /delt@ @b dup mul 4 @a mul @c mul sub def
   @b neg delt@ sqrt sub 2 @a mul div
   @b neg delt@ sqrt add 2 @a mul div
end
} def