What you'd essentially do is graph these functions and if it says, for example, x>0 then for x ≤ 0 you'd erase the function for that part (if you need help with this, you could draw a line at x=0 and go from there). The domain is what x values would fit there, and the range is what y values could result. For 9, any x value can be divided by 3 and multiplied by 4, and any y value could fit there, so the domain and range would be infinity - I challenge you to do the rest of the problems on your own!