find the constant rate of change

Answer:
- 2 ft/ s
Step-by-step explanation:
The rate of change is the slope m of the line.
Calculate m using the slope formula
m = [tex]\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex]
with (x₁, y₁ ) = (0, 80) and (x₂, y₂ ) = (40, 0) ← 2 points on the line
m = [tex]\frac{0-80}{40-0}[/tex] = [tex]\frac{-80}{40}[/tex] = - 2
Rate of change is - 2 ft/ s