The co-ordinates of a point P on the line 2x - y + 5 = 0 such that |PA - PB| is maximum, where A is (4,-2) and B is (2, -4) will be: A) (11, 27) B) (-11, -17) (Answer) C) (-11, 17) (Eliminated since it does not lie on the given line) D) (0, 5) Honest speaking, I don't know what to do in this question. I just attempted to prove that mirror image of A, P and B are non-collinear, but it doesn't changed the fact that I still can't reach to the answer. Basically, I just want to ask that what is the demand of the question? What I must try to prove? Sorry for being so much of a newbie, but I can't get over with it. I only ask for the direction in which I should work. I will try to do the rest. Thanks!