Explanation:
you mean, find the slope of the line that goes through (19, -2) and (-11, 10).
the slope is the ratio
y coordinate difference / x coordinate difference
when going from one point on the line to another.
so, for our points here
x changes by -30 (from 19 to -11).
y changes by +12 (from -2 to 10).
the slope is therefore +12/-30 = -2/5