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Simultaneous Equations Using Elimination Lesson Plan

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Lesson Plan #: AELP-ALG0004
Submitted by: Leslie Howe
Email: teachhowe2@hotmail.com
School/University/Affiliation: Farragut High School, Knoxville, TN Date: April 6, 2000

Grade Level(s): 9, 10, 11, 12, Higher Education, Vocational Education, Adult/Continuing Education


  • Mathematics/Algebra

Duration: 30 minutes Description: The Elimination method is an effective method for solving a system of two unknowns. This lesson provides students with immediate feedback using a computer program or online applet.

Goals: The student will be able to solve a system of two equations when there are two unknowns.

Objectives: Students will solve a given number of systems.

Materials: Online computer applet/program

Procedure: A system of two unknowns can be solved by multiplying each equation by the constant that will make the coefficient of one of the variables become the LCM (least common multiple) of the initial coefficients. Students may use the scroll bars on the indicated applet to multiply the equations by constants until the GCF is located. When the add button is activated after the correct constants are chosen one of the variables will be eliminated. The process can be repeated for the second variable. The student may enter the solution of the system by using scroll bars. When the check button is pressed the answer is evaluated and the student is given immediate feedback. (The same procedure can be done using the downloadable C++ application.)

After 5-10 correct responses the student should make the transition to paper and solve the equations without using the applet. The student can still use the applet to check the answer. The applet will generate problems in a random fashion. All solutions are integers.

Assessment: The lesson itself provides alternative assessment. The correct responses are recorded.

Useful Internet Resources:

* Online computer applet/program

* Free downloadable version of simultaneous equations