I believe your answer should be 105x squared-1475x+70
sorry i'm not really sure how to put the little two above the first x but my answer is mathematically correct.
Hello,
I don't see a graph you can edit your answer by putting a graph then I can help you.
Your friend --- Young Sinatra
Answer:

Step-by-step explanation:
Let
x------> the number of days
y----> the cost of renting a car
we know that
For 

For 
The rate is equal to

so

In this problem. the car has been rented for more than a week
therefore

The cost of renting a car is equal to

Answer:
see below
Step-by-step explanation:
Putting n=1 into the formulas eliminates the first two choices, since they evaluate to 3.57 and 0.85, respectively, not 4.2.
Putting n=2 into the formula eliminates the third choice, because you know that 4.2(0.15) < 3.57 without even using a calculator.
The only viable choice (and the correct choice) is the last one.