I'm doing a course on Solid State Physics and the textbook doesn't have a solutions manual. From what I've understood from previous students, the textbook does a great job of explaining the concepts but the problems are very hard and the textbook doesn't prepare you for them. My professor's office hours is only 2 hours a week in one time slot, and we don't have any tutorials for this course so the only help I can get is from the professor (which is minimal at best because I don't want to wait a week for feedback). The homework is mandatory and will be checked so I can't use another textbook. My only option is to use homework help services which are not reliable as they're a voluntary service. I feel like my best best is to gather as many of these services as possible. I'm aware of jiskha.com and allaboutcircuits.com but are there any others? I guess my other option is to hire a tutor.