var a,b,c,dk:real;
begin
writeln('Nhap a,b,c: '); readln(a,b,c);
if a=0 then
begin
if (b=0) and (c=0) then writeln('PT co nghiem dung voi moi x thuoc R') else
if b=0 then writeln('PTVN') else
writeln( ((0-c)/b):7:3 );
end else
begin
dk:=b*b - 4*a*c;
if dk < 0 then writeln('PTVN') else
if dk=0 then writeln( ((0-b)/(2*a)):7:3) else
writeln( ((b+sqrt(dk))/(2*a)):7:3, ((0-b-sqrt(dk))/(2*a)):7:3 );
end;
readln;
end.