The document discusses how to find the equation of a locus by considering an arbitrary point (x,y) on the curve and relating x and y based on the description of the curve. It provides examples of locus problems, such as finding the equation for all points equidistant from two given points, where the sum of distances to two given points is a constant, where the sum of squared distances to two given points is a constant, all points on a line with a given slope through a given point, and where the difference of distances to two given points is a constant.