The inverse of a function has all the same points as the original function, except that the x's andy's have been reversed. This is what they were trying to explain with their sets of points. For instance, supposing your function is made up of these points: { (1, 0), (–3, 5), (0, 4) }. Then the inverse is given by this set of point: { (0, 1), (5, –3), (4, 0) }. (Note that the order of the points doesn't matter; you can rearrange the points so thex's are "in order", or not. It's your choice.)