MYSQLI Multi Query Does not work in php

I can't seem to figure out why this query is not working. I am trying to run mysqli functions. I am trying to learn this technique. Any help is greatly appreciated.

<?php

$ID_CARTERA= '8';

$link = mysqli_connect("localhost","carteras_admin","!password","carteras_bdcarteras");

/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}

$query  = "SELECT    A.DES_ESTUDIOS Studies
FROM      det_personas_estudios A
      JOIN mcarteras B  ON ( A.ID_PERSONA = B.COD_ADMINISTRADOR )
WHERE     B.ID_CARTERA = $ID_CARTERA";
$query .= "SELECT    A.DES_ESTUDIOS Studies
FROM      det_personas_estudios A
      JOIN mcarteras B  ON ( A.ID_PERSONA = B.COD_ADMINISTRADOR )
WHERE     B.ID_CARTERA = $ID_CARTERA";

/* execute multi query */
if (mysqli_multi_query($link, $query)) {
do {
    /* store first result set */
    if ($result = mysqli_store_result($link)) {
        while ($row = mysqli_fetch_array($result)) {
            printf("%s\n", $row['Studies']);
        }
        mysqli_free_result($result);
    }
    /* print divider */
    if (mysqli_more_results($link)) {
        printf("-----------------\n");
    }
} while (mysqli_next_result($link));
}

/* close connection */
mysqli_close($link);
?>

---

Typo:

WHERE     B.ID_CARTERA = $ID_CARTERA;";
                                    ^---
$query .= "SELECT    A.DES_ESTUDIOS Studies