[AND_REY]

Вот пример:

procedure TForm1.Button1Click(Sender: TObject);
Var
K,X: Integer;
begin
K:= StrToInt(Edit1.Text);
X:= StrToInt(Edit2.Text);
Case K of
2: Edit2.Text:= IntToStr(X*X);
5: Edit2.Text:= IntToStr(X-2);
end;
end;