theorem
  (y |^ 3)+0*y^2+((3*a*c-b^2)/(3*a^2))*y + (2*((b/(3*a)) |^ 3)+(3*a*d-b*
  c)/(3*a^2)) = 0 implies for p,q st p = (3*a*c-b^2)/(3*a^2) & q = 2*((b/(3*a))
  |^ 3)+(3*a*d-b*c)/(3*a^2) holds Polynom(1,0,p,q,y) = 0;
