Module 7: Lesson 4

Module 7: Systems of Linear Equations

Lesson 4: Solving Linear Systems by Elimination

Focus

This photo shows a house with a sign that reads Yard Sale. There are people on the front lawn of the house, including a woman and a young girl looking at a girl’s pink dress that is for sale.

David Sacks/Lifesize/Thinkstock

Shopping can be a fun way to spend leisure time. It does not have to be an expensive endeavour. You can set a budget, or you can just go window shopping with some friends.

When the weather gets warmer, you can take your shopping outdoors and find some good bargains at garage sales or yard sales in your community. Perhaps you will uncover a missing piece to add to your special collection or an outfit that complements your current wardrobe.

Instead of shopping, you may discover multiple benefits if you decide to sell gently used items. First, you are eliminating unwanted items from your home. Second, you are doing your part for the environment by giving someone else the opportunity to reuse these products. Third, you can use the proceeds of the sale toward your own recreational pursuits.

In the last lesson you learned how to solve a linear system by using the substitution method. In this lesson you will learn a second algebraic technique for solving linear systems. This technique, called elimination, will depend on your ability to find or create matches from the equations in a system. Many of the math problems that you will encounter in this lesson are concerned with buying and selling items as a hobby.

Outcomes

 

At the end of this lesson, you will be able to

  • determine the solution of a system of linear equations by using the elimination method
  • verify the solution of a system of linear equations algebraically
Lesson Questions
  • In using the elimination method, how do you know whether equations need to be multiplied, added, or subtracted?
  • How does adding or subtracting the equations of a linear system affect the solution to the system?
Lesson Completion and Assessment

As you work through each lesson, complete all the questions and learning activities in your binder using paper and pencil, clearly labeling your work (they refer to this as your course folder). These include the Are you Ready, Try This, Share and Self Check questions. Check your work if answers are provided. Remember that these questions provide you with the practice and feedback that you need to successfully complete this course.
Once you have completed all of the learning activities, take the Lesson Quiz. This is the assessment for each lesson and is located under the Activities block on the left in moodle or under the Assess tab.


** Note – Share questions may have to be done on your own depending on your learning situation**


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