unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Edit1: TEdit;
    Edit2: TEdit;
    Edit3: TEdit;
    Edit4: TEdit;
    Edit5: TEdit;
    Edit6: TEdit;
    Edit7: TEdit;
    Edit8: TEdit;
    Edit9: TEdit;
    Button1: TButton;
    Label1: TLabel;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  a11,a12,a13,a14,a15 : real;
  a21,a22,a23,a24,a25 : real;
  a31,a32,a33,a34,a35 : real;
  v1,v2,v3,v4,v5,v6 : real;
  zz : real;


implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
zz := 0;

end;

procedure TForm1.Button1Click(Sender: TObject);
begin
a11 := StrToFloat(Edit1.Text);
a12 := StrToFloat(Edit4.Text);
a13 := StrToFloat(Edit7.Text);
a14 := StrToFloat(Edit1.Text);
a15 := StrToFloat(Edit4.Text);

a21 := StrToFloat(Edit2.Text);
a22 := StrToFloat(Edit5.Text);
a23 := StrToFloat(Edit8.Text);
a24 := StrToFloat(Edit2.Text);
a25 := StrToFloat(Edit5.Text);

a31 := StrToFloat(Edit3.Text);
a32 := StrToFloat(Edit6.Text);
a33 := StrToFloat(Edit9.Text);
a34 := StrToFloat(Edit3.Text);
a35 := StrToFloat(Edit6.Text);

 v1 := a11 * a22 * a33;
 v2 := a12 * a23 * a34;
 v3 := a13 * a24 * a35;

 v4 := a13 * a22 * a31;
 v5 := a14 * a23 * a32;
 v6 := a15 * a24 * a33;

zz := v1+v2+v3-v4-v5-v6;
Label1.Caption := FloatToStr(zz);
      
end;

end.