To find slope, use the formula:
slope = (y₂ - y₁)/(x₂ - x₁)
Note that it doesn't matter which one you set as (₁), or (₂), but you must set them correctly. Let:
(x₁, y₁) = (9,1)
(x₂, y₂) = (-3,-7)
Set each to corresponding variables.
(-7 - 1)/(-3 - 9)
Simplify.
-8/-12
Simplify. Divide -4 from the numerator and denominator
(-8/-12)/(-4/-4) = 2/3
2/3 is the slope of the line.
hope this helps