To find the slope of a line with given points, you divide the difference of y-coordinates by the difference of the x-coordinates of those same 2 points.
x's:-9-3=-12
y's:-1-(-6)=5
Then, you put the answer of the y's in the numerator, and x's in the denominator, giving you 5/-12, but you can't have a negative in the denominator, moving it up to become -5/12 as the slope.
