1. The problem statement, all variables and given/known data Find a and b such that the point (a,-5,b) lies on the line passing through (-3,-1,3) and (3,-4,9) 2. Relevant equations (maybe?) Component = P1P2 = (x2 - x1, y2 - y1) 3. The attempt at a solution Since it's a line passing through, I thought I could just add the two points together which gave me (0, -5, 12), but I did not get the right answer. So I thought maybe you have to get the component which would essentially be the terminal points of the 2 points which would form a new vector? P1P2 = (x2 - x1, y2 - y1) but then I'm not sure which would be the point to use for P2 and P1. We just started vectors like last week, and I'm still pretty newbie with this stuff :( I'm not totally sure how to interpret the question. What relevance does the -5 in (a, -5, b) have? It matches the addition of both of the points, but 0 and 12 do not work. Thanks for any help.