Explanation:
the slope is always the ratio "y coordinate change / x coordinate change" when going from one point of the line to another.
so, when going from (-2, 3) to (-3, 1)
x changes by -1 (from -2 to -3).
y changes by -2 (from 3 to 1).
therefore, the slope is
-2/-1 = 2/1 = 2