Program baitap;
Uses crt;
Var a,b,c,d,x,x1,x2:real;
Begin
Write('a='); Readln(a);

Write('b='); Readln(b);

Write('c='); Readln(c);
If a=0 then
   If b=0 then
       If c=0 then
Writeln('Co vo so nghiem')
       Else
Writeln('Vo nghiem')
   Else
Writeln('Co mot nghiem: x=',-c/b:5:3)
Else
Begin
d:=b*b-4*a*c;
If d=0 then
Writeln('Co nghiem kep: x=',-b/(2*a):5:3)
Else
If d<0 then
Writeln('Vo nghiem')
Else
Begin
x1:= (-b+sqrt(d))/(2*a);
x2:= (-b-sqrt(d))/(2*a);
Write('Co hai nghiem: x1=',x1:5:3,' ;x2=',x2:5:3);

End;
End;
Readln;
End.

Program GIAI_PHUONG_TRINH_BACII;

Uses CRT;

Var a,b,c,D,x,x1,x2: real;

Begin  

Clrscr;

Writeln('GIAI PHUONG TRINH BAC II: ');  

Writeln('-------------------------------------------'); 

 Write('Nhap he so a='); readln(a); 

 Write('Nhap he so b='); readln(b);  

Write('Nhap he so c='); readln(c);  

If a=0 then   

 If b=0 then     

 If c=0 then       

 Writeln('Phuong trinh co vo so nghiem')     

 Else Writeln('Phuong trinh vo nghiem')  

  Else Writeln('Phuong trinh co mot nghiem: x=',-c/b: 4: 2) 

 Else   

 Begin      D:=b*b-4*a*c;      

If D=0 then Writeln('Phuong trinh co nghiem kep: x=',-b/(2*a): 4: 2)     

 Else        If D<0 then Writeln('Phuong trinh vo nghiem')      

  Else          

 Begin           

  x1:=(-b-sqrt(D))/(2*a);            

 x2:=(-b+sqrt(D))/(2*a);           

  Writeln('Phuong trinh co 2 nghiem la x1= ',x1:4:2 ,' va x2= ',x2:4:2);          

  End;  

   End;

ReadlnEnd.