In order to calculate the slope in between the given points, use the following formula:
m = (y2 - y1)/(x2 - x1)
where (x1,y1) and (x2,y2) are the given points.
Replace the values of all coordinates:
m = (3 - 1)/(-2 - 7)
m = 2/(-9)
m = -2/9
Hence, the slope is -2/9