The cost function is an illustration of a linear function
The equation of the cost function is C(x) = 35 + 0.5x
The given parameters are:
-- the cost of renting a cooler
--- the rate per bottle
Assume the number of bottles in a cooler is x.
The cost function for the bottles in a cooler would be:

So, we have:

Evaluate the products

Hence, the equation is 
Read more about linear functions at:
brainly.com/question/15602982
Answer:
This relationship is a function
Step-by-step explanation:
While a function may not have two output values (y) assigned to the same input value (x), it may have two input values (x) assigned to the output value (y).
The table follows that rule
The only error you made is on problem 3. Everything else is correct. Nice work.
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Here is how to solve problem 3
Plug x = 1 into the equation and solve for y
-3x + y = 1
-3*1 + y = 1 ... replace x with 1
-3 + y = 1
y - 3 = 1
y - 3 + 3 = 1 + 3 .... add 3 to both sides
y = 4
<h3>The answer is 4</h3>
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Verifying the answer:
Plug (x,y) = (1,4) into the equation. Both sides should be the same number after simplifying both sides.
-3x + y = 1
-3*1 + 4 = 1 ..... replace x with 1; replace y with 4
-3 + 4 = 1
1 = 1
The answer is confirmed.
If you were to graph -3x + y = 1, which is equivalent to y = 3x+1, you'll find that the point (1,4) is on this line.
28000 / 5 days = $5,600 per day
Wednesday, Thursday, Friday = 3 days.
5,600 x 3 days = $16,800
The amount should be $16,800