Uses crt;
Var
a,b,c:real;
d:real;
BEGIN
write('Nhap a = ');readln(a);
write(' b = ');readln(b);
write('c = ');readln(c);
If a=0 then write('Phuong trinh vo nghiem !')
Else
Begin
D:=b*b-4*a*c;
If d=0 then write('Phuong trinh co nghiem kep x1=x2=',-b/(2*a));
If d<0 then write('Phuong trinh vo nghiem');
If d>0 then
Begin
Writeln('Phuong trinh co 2 nghiem phan biet:');
Write('x1=',(-b+sqrt(d))/(2*a));
Writeln;
Write('x2=',(-b-sqrt(d))/(2*a));
End;
End;
readln
END.