uses crt;
var a,b,c,d:longint;
//Chuong trinh con 1: nhap 3 so thuc a,b,c
procedure nhap;
begin
   write('Nhap a:');readln(a);
   write('Nhap b:');readln(b);
   write('Nhap c:');readln(c);
end;
//Chuong trinh con 2: xin loi minh chua hieu de lam
//Chuong trinh con 3: tinh delta
procedure delta;
begin
   d:=sqr(b)-4*a*c;
   writeln('Delta= ',d);  
end;
//Chuong trinh con 4: ket luan nghiem phuong trinh
procedure timnghiem;
begin
   if d<0 then writeln('Phuong trinh vo nghiem');
   if d=0 then writeln('Phuong trinh co nghiem kep: x1=x2=-(b/(2*a))=',-(b/(2*a))); 
   if d>0 then 
      begin
         writeln('Phuong trinh co 2 nghiem phan biet: ');
         writeln('x1=(-b+sqrt(delta))/2*a=',(-b+sqrt(d))/2*a:0:2);
         writeln('x2=(-b-sqrt(delta))/2*a=',(-b-sqrt(d))/2*a:0:2);
      end;
end;
//Chuong trinh chinh
begin
clrscr;
  Nhap;
  Delta;
  timnghiem;
readln;
end.