Computer-Based Algebra title

Solving a system of equations graphically is simple. Find the place where the two lines intersect and this is the solution to the system. This is because the point (or points) where the two lines meet is on both lines. So, this point satisfies both equations.

For example, in "Paying the Plumber," your two lines intersected when the plumbers worked for 3 hours and charged you $150. This point was the only point where both companies would charge you exactly the same amount of money for the same amount of work.

The point (3, 150) is a point on both lines and it satisfies both equations.

The solution to this system of equations is (3, 150).


Microsoft Excel icon

Open a new Excel document.

Create a table for the situation on the left.
Your table should include values for 0 to 7 computers.

Use the information in the situation (the story) to complete the table.

Create a graph in Excel. (If you get stuck, go back and watch the video on "Graphing in Excel.").

Title your graph, "Computer Sales"

You are trying to decide which computer sales company to work for.

A-1 Computer Sales will pay you $100 per day (whether you sell any computers or not). And for each computer you do sell each day, they will pay you an additional $50.

Computer Circuits will pay you only $60 per day (whether you sell any computers or not). And, for each computer you do sell each day, they will pay you and additional $60.

 

yahoo icon

Attach the Excel document with the table and graph below to an email.

Copy and paste the questions below into your email.
Then, write your answer to each question in the email

 

For the subject of your email, type Computer Sales .

1. Use your graph for the Computer Sales to answer these questions:

a. How many computers do you have to sell to make the same amount of money for both companies?

b. What is the solution to this system of equations?

2. Look back at your answer to Activity 1: Comparing Cell Phone Plans.

a. At what time, will the two companies charge you the same amount of money?

b. What is the solution to this system of equations?

Activity 2: Interactive Horizontal and Vertical Systems of Equations

Activity 3: Systems Graphing Calculator

 


Site Map: Home>Algebra Units>Systems of Equations>Solving Graphically

Activity 1: Solving Systems of Equations by Graphing

Links

NM Public Education Dept.
Albuquerque Public Schools
Del Norte High School
Link to Algebra Unit pages
Link to Resources pages