theorem Th4:
  for a, b, c, a9, b9, c9 being Complex holds (for x being
  Real holds Polynom(a,b,c,x) = Polynom(a9,b9,c9,x)) implies a = a9& b =
  b9& c = c9
proof
  let a, b, c, a9, b9, c9 be Complex;
  assume
A1: for x being Real holds Polynom(a,b,c,x) = Polynom(a9,b9,c9,x);
  then
A2: Polynom(a,b,c,-1) = Polynom(a9,b9,c9,-1);
  Polynom(a,b,c,0) = Polynom(a9,b9,c9,0) & Polynom(a,b,c,1) = Polynom(a9,
  b9,c9,1) by A1;
  hence thesis by A2;
end;
