Find the slope of the line that contains the points.
(4,54) and (9,24)

Given two points (x₁,y₁) and (x₂,y₂) the slope of the line that passes thorugh these points is:
m=(y₂-y₁)/(x₂-x₁)

We have two points (4,54) and (9,24) therefore the slope of the line that contains these points is:

m=(24-54)/(9-4)=-30/5=-6

the slope of the line that contains these points is m=-6