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39 votes
100 POINTS HEELP PLSSS!!!

100 POINTS HEELP PLSSS!!!-example-1
User Skrrgwasme
by
2.8k points

2 Answers

17 votes
17 votes

Answer:

1. (4, 360)

2. total cost at both repair shops is the same

3. Amy's Auto Repair: $280

Explanation:

Given system of equations:


\begin{cases}y=100+65x\\y=40+80x\end{cases}

Question 1

Solve by using the Substitution Method:


\implies 40+80x=100+65x


\implies 40+80x-65x=100+65x-65x


\implies 40+15x=100


\implies 40+15x-40=100-40


\implies 15x=60


\implies 15x / 15=60 / 15


\implies x=4

Substitute the found value of x into one of the equations and solve for y:


\implies y=40+80(4)


\implies y=40+320


\implies y=360

Therefore, the point of intersection is (4, 360)

Question 2

The two lines intersect at (4, 360). This means that the total cost at both repair shops is the same when it takes 4 hours to repair the car. The cost at this time is $360.

Question 2

To find the cost at both repair shops if it takes 3 hours to fix the car, substitute x = 3 into both equations and solve for y:

Mike's Repair shop:


\implies y=100+65(3)


\implies y=100+195


\implies y=295

Amy's Auto Repair:


\implies y=40+80(3)


\implies y=40+240


\implies y=280

Therefore, Amy's Auto Repair company is the cheapest at a cost of $280.

User Jseb
by
2.4k points
20 votes
20 votes

Answer:

See below.

Explanation:

1.

y = 100 + 65x

y = 40 + 80x

100 + 65x = 40 + 80x

-15x = -60

x = 4

y = 100 + 65x = 100 + 260 = 360

(4, 360)

2.

The lines intersect at the point (4, 360).

At the point of intersection, where x = 4, it shows that by doing 4 hours of labor, both shops cost the same.

3.

Mike's:

y = 100 + 65x = 100 + 65(3) = 100 + 195 = 295

Amy's:

y = 40 + 80x = 40 + 80(3) = 40 + 240 = 280

For 3 hours of labor, Amy's shop is cheaper at $280. Mike's costs $295.

User Nicolagi
by
3.4k points