2 Syntax Questions

I'm very new to PHP. I've scanned the manual for these two, but I can't quite find the answers: 1. Is the following legal? <INPUT TYPE="hidden" NAME="user_id" VALUE="<? echo $user_id ?>"> Or is it necessary to do this? <? echo("<INPUT TYPE=\"hidden\" NAME=\"user_id\" VALUE=\"".$user_id."\">"); ?> 2. If I use the <? if: else: endif; ?> syntax to avoid echoing larger blocks of HTML, within those statements, is it legal to use the standard <? if(...) {...} else {...} ?> syntax? Thanks! Mark