#include<stdio.h>
#include<stdlib.h>
#include<math.h>
int main (void)
{
   double a, b, c;
   {
      char line[8];

      printf ("ax*x+bx+c=0\nsaisissez a=");
      fflush (stdout);
      fgets (line, sizeof line, stdin);
      a = strtod (line, NULL);

      printf ("saisissez b=");
      fflush (stdout);
      fgets (line, sizeof line, stdin);
      b = strtod (line, NULL);

      printf ("sasissez c=");
      fflush (stdout);
      fgets (line, sizeof line, stdin);
      c = strtod (line, NULL);
   }

   if (a == 0)
   {
      if (b == 0)
      {
         if (c == 0)
         {
            printf ("infinite de solutions\n");
         }
         else
            printf ("pas de solutions\n");
      }
      else
      {
         double x1 = -c / b;
         printf ("la solution x=%f\n", x1);
      }
   }
   else
   {
      double delta = b * b - 4 * a * c;
      if (delta > 0)
      {
         double x1 = (-1 * b + sqrt (delta)) / (2 * a);
         double x2 = (-1 * b - sqrt (delta)) / (2 * a);
         printf ("les solutions sont x1=%f et x2=%f\n", x1, x2);
      }
      else
      {
         if (delta < 0)
            printf ("pas de solution");
         else
         {
            double x1 = -b / (2 * a);
            printf ("solutions x1=%f", x1);
         }
      }
   }
   return 0;
}