After failing the course, you will usually take the exam next semester or next semester. However, there are credit requirements. For example, you are required to take up to 20 credits in the next semester, and you have to retake advanced mathematics when your courses are full of 20 credits in the next semester, so you have to drop out of one of the courses in the next semester to make room for credits to take advanced mathematics. Therefore, you must re-choose the courses you give up next semester. So don't fail.