Make it appear more rewarding to her. She doesn't think of the real rewards schoolwork gives her, but if you reward her with something she wants - within reason, of course and decided by you - then she will be more likely to complete the work and then when she doesn't, take something she loves away.
So, for example: if she has been begging for a new pair of shoes and she completes all her work, maybe take her out shopping with a budget you can afford and she can pick out the ones she wants. If she doesn't get her work done, or you find out she didn't turn the assignment in then take away some privileges - if she has an mp3 player or smartphone, take it away until she learns her lesson.
You have to get really stoked about homework. You have to be active in helping them with it, and interested in what they are learning. When my kids were young, I went back to college, and we would be at the table doing homework together. They thought that was so awesome. Check mom out, she's doing her homework! =)
I believe you have to get involved. Help him or her with it. Show them how important it's to you for them to do it by being involved. Don't give up make them bring books home. Contact the teachers to know what they need to do and what homework they have.
Let them know how tough the real world is, and maybe that will help, because work and all that comes with it is what really is tough! Life goes fast, this is one more bump in the road,and there are many more ahead!