Let the line p be the perpendicular bisector of A = (24,7) and B = (3,-4). Given that AB meets p at C = (x,y), what is 2x - 4y? I'm really stuck.
P is going to meet A and B at their midpoint, which is (27/2, 3/2). 2x - 4y = 27 - 3*2 = 21.
