Answer:
Step-by-step explanation:
https://drive.google.com/open?id=1QAvmjDjuwgFX0mUdHlWmqMSCJcOVMw2X
30 books
y =1 /2 x+ 5
-16.8 = m(4)
-16.8 / 4 = -4.2
So the constant rate is -4.2.
Hope this Helps!!