Will give brainliest b. describe the function over each part of its domain. state whether it is constant, increasing, or decreasing, and state the slope over each part.

When x <= 8000

The cost remains constant at 0.35 when x increases from 0 to 8000

The slope of cost function over this part is 0

When 8000 < x <= 20000

The cost remains constant at 0.75 when x increases from 8000 to 20000

The slope of cost function over this part is 0

When 20000 < x <= 42000

The cost decreases when x increases from 20000 to 42000

The slope of cost function

m= -5 × 10^-6