Answer:
slope = - 50
Step-by-step explanation:
Calculate the slope m using the slope formula
m = [tex]\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex]
with (x₁, y₁ ) = (4, 2400) and (x₂, y₂ ) = (12, 2000) ← 2 points on the line
m = [tex]\frac{2000-2400}{12-4}[/tex] = [tex]\frac{-400}{8}[/tex] = - 50
