It is required that you find the slope of the line passing between two points.
The given points are:

The formula for the slope of the line passing through two points (x₁,y₁) and (x₂,y₂) is:

Substitute the given points (x₁,y₁)=(12,-3) and (x₂,y₂)=(5,-9) into the formula:

Calculate the value of m to find the slope:

The required slope of the line is 6/7.