You have given us no clue what course this problem comes from so it is very difficult to know what advice to give you. I'd start by recognizing that you must provide at least three different solutions. If this is for a design class, you may want to explore more than just three solutions, and you may very well to want to explore the fact that you have three dimensions to play with. If this is for a math class, you probably can forget the third dimension unless you think that might give you extra credit.
Now the functions don't care from what angle they are viewed, but you need to think about the functions so a frame of reference would be helpful. Let's say x measures from front to back, y measures from top to bottom, and z measures from left to right along the front of the house (or right to left along the back of the house. If you are going to just vary the roof with respect to two dimensions and you want to sketch things, what plane is most useful to visualize, zy, zx, yx?