For up to 25 extra homework points (added into your homework point total), you can fix anything you did wrong on problems 2-6 of the exam. Each problem is worth 5 points; if you got full credit for that problem, note that you don't have to do anything but turn in the assignment to get the corresponding points. For problems that you received only partial credit on, you must rewrite the full solution. The problem you chose not to do on the exam is also worth 5 points.
You should write up your repaired solutions on a separate sheet of paper, and take care to do it reasonably and readably. Turn in your original exam (or a Xerox of it) along with the rewritten problems.
If you like, you can apply this to the "proof" part of the upper-division writing requirement of the math major. The relevant problems are problems 4 and 6; these must be written in a clear, readable manner and be completely correct to count for the requirement. If you wish to do this, please indicate this on your paper so I can treat it accordingly.
Here is a copy of the midterm. You can put your fixes on the corresponding pages if you want, or use plain paper.