program Giai_PTB2;

uses crt;

var a,b,c:real;

    D,x1,x2:real;

begin

     clrscr;

     while(a=0)do

          begin

               write('a = ');

               readln(a);

          end;

     write('b = ');

     readln(b);

     write('c = ');

     readln(c);

     D:=b*b-4*a*c;

     if D<0 then

        writeln('Phuong trinh vo nghiem.')

     else

         begin

              x1:=(-b-sqrt(D))/(2*a);

              x2:=-b/a-x1;

              writeln('x1= ',x1:8:3,'  x2= ',x2:8:3);

         end;

     readln

end.

program Nam_nhuan;

uses crt;

var N,SN:integer;

begin

     clrscr;

     write('Nam: ');

     readln(N);

     if(N mod 400=0)or((N mod 4=0)and(N mod 100<>0))then

          SN:=366

     else

         SN:=365;

     writeln('So ngay cua nam ',N,' la ',SN);

     readln

end.

program UCLN;

uses crt;

var M,N:integer;

begin

     clrscr;

     write('M,N= ');

     readln(M,N);

     while M<>N do

           if M>N then M:=M-N else N:=N-M;

     writeln('UCLN= ',M);

     readln

end.

program Tong_ngich_dao;

uses crt;

var S:real;

    a,N:integer;

begin

     clrscr;

     write('Hay nhap gia tri a: ');

     readln(a);

     S:=1.0/a;

     N:=0;

     while not(1/(a+N)<0.0001) do

           begin

                N:=N+1;

                S:=S+1.0/(a+N);

           end;

     writeln('Tong S la :',S:8:4);

     readln

end.

program Pi_ta_go;

uses crt;

var a,b,c:integer;

    a2,b2,c2:longint;

begin

     clrscr;

     write('a,b,c:');

     readln(a,b,c);

     a2:=a;

     b2:=b;

     c2:=c;

     a2:=a2*a;

     b2:=b2*b;

     c2:=c2*c;

     if(a2=b2+c2)or(b2=a2+c2)or(c2=a2+b2)then

         writeln('Ba so da nhap la bo so Pi-ta-go')

     else

         writeln('Ba so da nhap khong la bo so Pi-ta-go');

     readln

end.

program GaCho;

uses crt;

var ga,cho:integer;

begin

     clrscr;

     ga:=1;

     cho:=36-ga;

     while ga*2+cho*4<>100  do

         begin

              ga:=ga+1;

              cho:=36-ga;

         end;

     writeln('Ga : ',ga:3);

     write('Cho: ',cho:3);

     readln

end.

program Tuoi;

uses crt;

var tcha,tcon,dem:integer;

begin

     clrscr;

     while not((tcha>tcon*2)and(tcha-tcon>=25)) do

           begin

                write('Nhap tuoi cha, tuoi con : ');

                readln(tcha,tcon);

           end;

     dem:=0;

     while not(tcha=tcon*2) do

           begin

                tcha:=tcha+1;

                tcon:=tcon+1;

                dem:=dem+1;

           end;

     write('Tuoi cha gap doi tuoi con sau ',dem,' nam');

     readln

end.

program Lai;

uses crt;

var A,B:real;

    dem:integer;

begin

     clrscr;

     write('Nhap so tien A: ');

     readln(A);

     write('Nhap so tien tong cong B: ');

     readln(B);

     dem:=0;

     while B>A+dem*A*0.003 do

           begin

                dem:=dem+1;

           end;

     write('Ban nhan duoc ',B:8:3,' sau ',dem,' thang');

     readln

end.