1. The problem statement, all variables and given/known data Tangent to C at point P(2,7) has an equation of y=3x+1. Point Q also lies on C and is perpendicular to the tangent, show that the X-coordinate is [1/3(2+√6)] 2. Relevant equations curve C has equation y= x3-2x2-x+9 dy/dx = 3x2-4x-1 3. The attempt at a solution gradient of normal has to = -1/3, right? considering that the tangent that is is perpendicular to is +3 I'm not sure as, the point that the normal is passing through hasn't been specified. Here is the actual question: http://i259.photobucket.com/albums/hh299/the-real-guitar-hero/CapturePNGnnn_zpsd170ce09.png Part C.