Select2 multiple values and if/then

I am trying to have a div show if 2 options in a select2 box are chosen using jquery but am unsuccessful.

For example - my 2 choices are First and Second:

<select id="choose1" multiple="multiple">
<option value="first">First</option>
<option value="second">Second</option>
</select>

I have 2 divs that hidden:

<div id="first">
ABC
</div>
<div id="second">
XYZ
</div>

$('#first').hide();
$('#second').hide();

And now my jquery to show the divs:

$('#choose1').select2();

$('#choose1').change(function () {
    var val = $(this).val();
    var x = 'first';
    var y = 'second'
    var z = ['first','second'];

    if (val == x) {
        $('#first').show();
    }

  else if (val == y) {
    $('#second').show();
  }

  else if (val == z) {
  $('#first').show();
  $('#second').show();
  }

    });

Any ideas on how I can get this to work?

Thanks.