Вычисление определителя матрицы (помогите исправить ошибку)

program zav9;
uses crt;
const n=3;
var a: array [1..n,1..n] of integer;
i,j,d: integer;
begin
writeln ('Shkurko');
for i:= 1 to n do
begin
for j:= 1 to n do
begin
a[i,j]:= random(10);
write (a[i,j]:4);
end;
writeln;
end;
d:= (a[1,1]*a[2,2]*a[3,3])+(a[2,1]*a[3,2]*a[1,3])+(a[1,2]*a[2,3]*a[3,1])-(a[3,1]*a[2,2]*a[1,3])-(a[3,2]*a[2,3]*a[1,1])- (a[1,2]* a[2,1]*[3,3]);
writeln('vyznachnyk masivu =',d);
readln;
end.

program zav9;
uses crt;
const n=3;
var a: array [1..n,1..n] of integer;
i,j,d: integer;
begin
for i:= 1 to n do
begin
for j:= 1 to n do
begin
a[i,j]:= random(10);
write (a[i,j]:4);
end;
writeln;
end;
d:= (a[1,1]*a[2,2]*a[3,3])+(a[2,1]*a[3,2]*a[1,3])+(a[1,2]*a[2,3]*a[3,1])-(a[3,1]*a[2,2]*a[1,3])-(a[3,2]*a[2,3]*a[1,1])- (a[1,2]* a[2,1]*[3,3]);
writeln('vyznachnyk masivu =',d);
readln;
end.

program zav9;
uses crt;
const n = 3;
var a: array [1..n,1..n] of real;
    i,j: integer;
    d1,d2:real;
begin
  clrscr;
  randomize;
  for i:= 1 to n do
  begin
    for j:= 1 to n do
    begin
      a[i,j]:=random*10;
      gotoxy(i*7,j);
      write(a[i,j]:4:2);
    end;
    writeln;
  end;
  d1:= (a[1,1]*a[2,2]*a[3,3])+(a[2,1]*a[3,2]*a[1,3])+(a[1,2]*a[2,3]*a[3,1]);
  d2:= -(a[3,1]*a[2,2]*a[1,3])-(a[3,2]*a[2,3]*a[1,1])-(a[1,2]*a[2,1]*a[3,3]);
  writeln('Determinant = ',(d1+d2):7:4);
  readln;
end.