Answer:
The cost to rent a trailer for 2.8 hours is $21.4.
The cost to rent a trailer for 3 hours is $23.
The cost to rent a trailer for 8.5 hours is $67.
Explanation:
Let x be the number of hours.
It is given that the charge to rent a trailer is $15 for up to 2 hours plus $8 per additional hour or portion of an hour.
The cost to rent a trailer for x hours is defined as

For x>2, the cost function is

We need to find the cost to rent a trailer for 2.8 hours, 3 hours, and 8.5 hours.
Substitute x=2.8 in the above function.

The cost to rent a trailer for 2.8 hours is $21.4.
Substitute x=3 in the above function.

The cost to rent a trailer for 3 hours is $23.
Substitute x=8.5 in the above function.

The cost to rent a trailer for 8.5 hours is $67.
Written all the ordered pairs in the form of (hours, cost).
(2.8,21.4), (3,23) and (8.5,67)
Plot these points on coordinate plane.