The illumination due to a point light source with strength k at a distance r away from its given formula I=k/r^2. Let a point light source placed at the origin of the x-axis have strength 64 and let a point light source placed at x=10 on the x axis have strength 27. At what position on the x-axis between 0 and 14 is the sum of the illumination from these two point light sources at a global minimum, where x is between 0 and infinity. Can you please include a diagram.