While you may be seeing other signs that your daughter has no desire to learn, from the information in your question, I see nothing to warrant that conclusion.
Rather than settle on a negative mind set regarding your child's motivation, I would encourage you to take the following steps to find out what is going on.

 It seems to me that six hours is indeed a lot of time for the amount of work you mention. If the six hours are really spent on the work, then it is important to find out what is slowing her down.  If the six hours are spent distracted, watching TV, or in activity unrelated to the work, then you might be dealing with a behavioral issue rather than a homework issue.

But going on what you have said, I think the help you can offer might be a little broader than helping her with her homework on a given night. I recommend a bit of "research"  in order to find out what is really going on. I suggest you set up a meeting with your daughter's teacher and find out how your child is actually performing in school in relation to her peers.  If everyone else is able to manage the amount of homework that is expected, I would encourage you to discuss with the teacher what his/her thoughts are about what is slowing your child down. If you find out that everyone else is able to do the same amount of work in much less time, you may want to talk to the guidance counselor at your daughter's school to see about some psychological testing to uncover any learning problems your child may have.

As for the homework help itself, I see nothing wrong with offering help short of actually supplying the answers. (And occasionally that is not a terrible thing either.)  But help in the moment may have more to do with giving encouragement, helping her to follow directions, finding out what part of the question she might not understand, seeing if she needs a break when her concentration wanes, offering a snack, and even calling it "quits" on a given night.

 If she is overwhelmed, overly frustrated, or unduly tired it is okay to let her stop. Not having the homework completed occasionally will not ruin a child's education, but  getting overwhelmed or overly frustrated can de-motivate a student. On those occasions, when you and she call it quits, you might send a note to the teacher, letting him/her know how hard your girl tried and asking the teacher to offer the assistance with the homework.  You can give up on a piece of homework without giving up on your daughter.

Collaboration with the teachers is an important aspect of helping children successfully achieve their education.  If your daughter is bright, she may need a boost with some of her work on some nights and some nights she just may need some intermittent breaks, or need to stop for the night, and talk to the teacher in the morning. Use your judgment. These days most teachers are flexible and eager to assist their students, especially when they know the child is not just "blowing off" the work.

However, whatever you decide on any particular night, please bear this in mind.
Your attitude and mind set about your daughter will be quite influential, even if  is subtle. Do your best to believe in her abilities as well as her willingness to learn, as you research the facts of the problem, and make decisions about how to help.  

Bette J. Freedson, LICSW, LCSW, CGP