The equation to find the slope of a line is "y2 - y1 / x2 - x1"
Our second y coordinate is 5 and our first y coordinate is 2.
5 - 2 = 3.
Our second x coordinate is -7, and our first x coordinate is 12.
-7 - 12 = -19.
We now have 3 / -19
3 / -19 = ~-0.158
Therefore, the slope of the line is ~-0.158