Cả 3 mình gửi trong ảnh ạ 

Câu 2 bạn sửa thành câu 3 ạ 

B1: 

uses crt;

var a,b,c,S,C,p:integer;

begin

write('nhap a:');readln(a);

write('nhap b:');readln(b);

write('nhap c:');readln(c);

if (a<b+c) or (b<a+c) or (c<a+b) then 

begin

writeln(' Day la tam giac'):

C:= a+b+c;

p:=C/2;

S:=sqrt(p*(p-a)*(p-b)*(p-c));

writeln('Chu vi:',C);

writeln('Dien tich:',S);

end else writeln('Day ko phai tam giac');

readln;

end.

B2:

uses crt;

var a:integer;

begin

write('nhap a:');readln(a);

if (a mod 2)=0 then writeln('Day la so chan') else writeln('Day la so le');

readln;

end.

B3:

uses crt;

var a,b,x,S:integer;

begin

write('nhap a:');readln(a);

write('nhap b:');readln(b);

S:=0;

x:=(S-b)/a;

writeln('x=',x);

readln;

end.