You use the slope formula:

And you plug in the points. The first point is (-4,4), and the second point is (0,-1)
y₂ is the second y value/coordinate (which is -1)
y₁ is the first y value/coordinate (which is 4)
x₂ is the second x value/coordinate (which is 0)
x₁ is the first x value/coordinate (which is -4)




That is your slope