1.

program ct;

uses crt;

  var a, b, c: integer;

begin

  write('Nhap a = '); readln(a);

  write('Nhap b = '); readln(b);

  write('Nhap c = '); readln(c);

  if (a+b<=c) or (a+c<=b) or (b+c<=a) then write('a, b, c khong phai la 3 canh cua tam giac') else

      if (a=b) and (a=c) then write('a, b, c la 3 canh cua tam giac deu') else

                if (a=b) or (a=c) or (b=c) then write('a, b, c la 3 canh cua tam giac can') else

                          write('a, b, c là 3 canh cua tam giac thuong');

  readln

end.

2.

1, Program giai_phuong_trinh_bac_nhat;

uses crt;

var a,b:integer;x:real;

Begin

       clrscr;

       write('Nhap a= ');readln(a);

      write('Nhap b= ');readln(b);

       x:=-b*a;

       writeln('nghiem cua phuong trinh la x= ',x);

        readln;

End.