Question

Part A: Eveline rented a car at $180 for 4 days. If she rents the same car for 9 days, she has to pay a total rent of $325. Write an equation in the standard form to represent the total rent (y) that Eveline has to pay for renting the car for x days. (4 points)

Part B: Write the equation obtained in Part A using function notation. (2 points)

Part C: Describe the steps to graph the equation obtained above on the coordinate axes. Mention the labels on the axes and the intervals. (4 points)

Answer 1

Explanation:

Part A

We will use the slope intercept form of the line and then convert later.

Equation

y = mx + b is the general form

Givens

Two data points

(4,180)

(9,325)

Solution

325 = 9x + b

180 = 4x + b Subtract

145 = 5x Divide by 5

145/5 = 5x/5 Do the division

29 = x This represents the cost / day

180 = 4x + b Substitute x = 29 to find b

180 = 4*29 + b Combine

180 = 116 + b Subtract 116 from both sides.

180 - 116 = b

64 = b

Solution for y = mx + b

y = 29x + 64

In Standard form this is

- 29x + y = 64 But the first number must be plus

29x - y = - 64 <<<< Answer A

Part B

y = 29x + 64

f(x) = 29x + 64

Part C

The graph is shown below. Various points are filled in using y = 29x + 64. The y intercept is (0,64) which is labeled. Let x = 1 , 2, 3, 4, ... 10 (which is arbitrary). This may be more easily done on a spreadsheet if you know how to use one to make graphs.