Question

Two car washes charge a basic fee plus a fee based on the number of extras that

Answer 1

Answer:

a. The first car wash charges more for the basic fee

b. 6 extras must be chosen for the total cost to be the same

Explanation:

The complete question is shown in the attached diagram

The general form of the linear equation is:

y = mx + c where m is the slope and c is the y-intercept

The y-intercept represents the initial value which, in the given problem, is the basic fee

For the first car wash, we are given the equation:

y₁ = x + 9

Now, we will start by getting the equation for the second car wash:

1- getting the slope:

$m = \frac{y_{2}-y_{1}}{x_{2}-x_{1}} =\frac{12-9}{4-2}=1.5$

The equation now is: y = 1.5x+c

2- getting the y-intercept:

To get the y-intercept, we will simply choose a point, substitute with it in the equation from 1 and solve for c. I will use point (2,9)

y = 1.5 x + c

9 = 1.5 (2) + c ............> c = 6

The equation for the second car wash is:

y₂ = 1.5x + 6

Part 1:

As mentioned above, the y-intercept represents the basic fee

For the first car wash:

y₁ = x + 9 ................> The basic fee is $9

For the second car wash:

y₂ = 1.5x + 6 ..............> The basic fee is $6

It is clear that the basic fee for the first car wash charges more for the basic fee

Part 2:

In both equations, x represents the number of extras. We want the total cost to be the same. So, we will simply equate y₁ and y₂ and solve for x

x + 9 = 1.5x + 6

1.5x - x = 9 - 6

0.5x = 3

x = 6

Let's verify:

For x = 6:

y₁ = x + 9 = 6 + 9 = $15

y₂ = 1.5x + 6 = 1.5(6) + 6 = $15

Total cost is the same. This means that 6 extras must be chosen for the total cost to be the same

Hope this helps :)