|   | 1 |  initial version  | 
polygens(QQ, 'x') returns a tuple consistantly with polygens(QQ, 'x, y') which also returns a tuple. If you want x to get the unique element of that tuple, not the tuple itself, you can do:
sage: x, = polygens(QQ, 'x')
or (equivalently):
sage: (x,) = polygens(QQ, 'x')
 Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.
 
                
                Copyright Sage, 2010. Some rights reserved under creative commons license. Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.