check the picture below.

as you may already know, tan⁻¹ function has a range of (π/2, -π/2), and therefore it will give us the negative counterpart angle, however, the positive one we can get it by going the other way, 360 - θ.
PART A
To form the equation to represent total rent, we first need to establish the changing rate and the fixed cost. Changing rate is the fee for every one day the car is rented and fixed cost is the initial cost of the car rental.
To find the changing rate we divide the cost difference between two days by the difference of days
We have
$180 = 4 days
$ 325 = 9 days
The changing rate is

The table below shows the working out of the price for each day the car is rented. We work out that day 0 cost $63 which means this is the fixed cost
Hence, the equation of total cost is

, where

is the total cost and

is the number of days
PART B:
Using the function notation means we will use

instead of

, so the equation is

PART C:
To graph the function, we first need to set the scales on the x-axes and y-axes.
The scale on x-axes could go up in ones but must start from 0
The scale on y-axes, since it is much bigger values, we can go up in 50
We then plot on the graph for each pair of days and cost. The plots should give us a straight line graph
One example of the graph is shown below
A) Look at the coordinates of the four dots:
(0,0) (150,50) (300,100) (450,150)
Divide the x's by the y's ( other than the (0,0) one:
150/50 = 3
300 / 100 = 3
450/150 = 3
The ratio is the same for all of them and the first set is (0,0) so it is a direct variation graph.
B) The constant of proportionality is the ratio found above by dividing the X values by the Y values, which is 3.
Number is n
Three times the sum of a number and 4.
= 3* ( n + 4) = 18
3n + 12 = 18.
3n = 18 - 12.
3n = 6
n = 6 / 3.
n = 2.
If the students are hiking at 4 km/h, you'll need to use the schedule to find <em>the total number of hours they spent hiking</em> and multiply it by that rate. According to the activity column, how many time chunks are they hiking for, and how long does each of them last? You can use that information to help answer the question.