You cannot use JS variable directly to PHP like that. use ajax instead:
JS
$("#business_list_table").on('click', '.view_btn', function post() {
    // get the current row
    var currentRow = $(this).closest("tr");
    var Business_id_value= currentRow.find("td:eq(1)").text(); // get current row 2nd T;
    $.post('', {Business_ID: Business_id_value}, function(result){
        $('table tbody').html(result);
    });
});
PHP
if (isset($_POST['Business_ID'])) {
    $Business_ID = $_POST['Business_ID'];
    $conn = mysqli_connect("localhost", "root", "", "bpsystem");
    if ($conn->connect_error) {
        die("Database connection failed:" . $conn->connect_error);
    } else {
        $sql = "SELECT * FROM business_tb WHERE Business_ID='$Business_ID';";
        $result = $conn->query($sql);
        if ($result->num_rows > 0) {
            // output data of each row
            while ($row = $result->fetch_assoc()) {
                echo "<tr >";
                echo "<td>BUSINESS NAME</td>";
                echo "<td>" . $row['Business_Name'] . "</td>";
                echo "</tr>";
                echo "<tr >";
                echo "</tr>";
            }
        }
    }
}