This is a homework problem I am trying to do. I have done part 2i) as well as 2ii) and know how to do the rest. I am stuck on 2iii) and 2vii). I truly dont know 2vii because it could be some special case I am not aware of. As for 2iii) I tried to approach it the same way as I did 2ii in which case I said you could take the 2 equations and use substitution method to isolate each variable and plug it in to find your variable values but 2iii) that doesnt work so I dont know how to do it.