I'm sure much ridicule will follow, but my experience is that a "bad instruction" is not an excuse for failure. A student with initiative who really wants to learn any material and realizes "Good God, this instructor sucks...or this textbook is useless..." will do what it takes to get the information they need. Both claims may be true however, those claims don't relieve a student from learning and understanding the material at sufficient levels of understanding. My point is this, once the student graduates and begins to represent themselves as a "B.S. of XXXX engineering" (or other discipline), your perspective employers will assume you have the basic understanding of the materials associated with that level of college achievement. They are not going to care one bit about textbook issues, bad instructors or anything else related to YOUR inadequacies. If you don't meet the minimum requirements of the level of education you are presenting to them then you will simply be removed from the job. You can either do the job or not... it's just that simple and that becomes evident in the first 2 months of employment. This is why many, many engineering firms have a 2 or 3 month probation period to see if you have what it takes or just "got passed along by the college" so they can get their funds from the government based on the student quota they need to "push thru".
If your professor "sucks", find a way past him. If the textbook "sucks", find another one. If your still having issues, this forum can help some, youtube can help some, "Art of Problem Solving" can help some. Almost all colleges/ universities offer tutoring. The bottom line is there is no real excuse for academic failure particularly in today's society. There's plenty of resources available to achieve what you want to achieve. If something doesn't work for you then try another way. If all your instructors suck, find another college. It's totally up to you. I'm trying to push you to become dependent on yourself in achieving your academic goals. I believe you can do it, simply because you showed a minimum amount of initiative by starting this thread. YOU do what it takes. On one hand, the college may hand you a degree with no effort on your part, but be assured, employers will not simply hand you a paycheck without commensurate effort on your part.