Monday, May 4, 2009

Problem 27 - GMAT Coordinate Geomery

In a coordinate system, points A and B have xy-coordinates (5, 2c) and (6, c^2), respectively. If points A and B lie on line k, which has slope 8, then c could equal

(A) -4
(B) -3
(C) 1
(D) 2
(E) 4


  1. formula for slope; y2-y1/x2-x1
    => (2c-c^2)/(5-6)=8
    Simplify and organize on one side of the equal sign, then you get; c^2-2c-8=0
    Either c=4 or c=-2
    => c=4 => E