SHOW YOUR WORK!!! Marking best answer as brainliest :))

Answer:
-25
Step-by-step explanation:
You must first pick two points. I picked the points of (4, 400) and (8, 300). You can pick different points and still get the right answer.
Subtract the y's and the x's. Divide the difference of y by the difference of x.
400 - 300 = 100
4 - 8 = -4
100/-4 = -25
The slope, or rate of change, is -25.