Hello,
Canadian (I live near Montreal) expert in Fortran programming here, I have more than 15 years of Fortran programming experience.
So, you want Problem 1.c, the problem is that in order to implement c you will need to do a and b first because you need a Gauss solver. This also mentions some pages from your course notes, I will need access to these.
For Problem 3, you will also need the Gauss solver from Problem 1!
Thanks and let me know if you are interested to work with me,
Danny