The rate of change of coordinates is what is called slope. Based on the given question, you are to find the slope and the slope is expressed as;
m = y2-y1/x2-x1
Given the coordinates (-1,3) and (-4,8)
x1 = -1, y1 = 3, x2 = -4 and y2 = 8
Substitute the values into the slope formula as shown;
m = 8-3/-4-(-1)
m = 5/-4+1
m = 5/-3
Hence the rate of change of the points (-1,3) and (-4,8) is -5/3