AB has a midpoint at (4,6). If A has a coordinates of (0,4), find the coordinates of B

Suppose you are analyzing the relationship between time and distance given in a table, and there are 4 values for each quantity. you divide distance 2 minus distance 1 by time 2 minus time 1.you then divide distance 4 minus distance 3 by time 4 minus time 3 and get a different answer. what can you say about the relationship?