Program Bai_lam;
Uses crt;
Var a,b,c,d,x,x1,x2:real;
Begin
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);
Write('Phuong trinh co hai nghiem: ‘);
Writeln(‘ x1=',x1:4:2,' va x2=',x2:4:2);
End;
End;
Readln;
End.