Methods of Solving a System of Linear Equations in Two Variables

Learning Resource Type

Classroom Resource

Subject Area

Mathematics

Grade(s)

8

Overview

This resource provides examples and explanations on how to solve a system of two linear equations in two variables (unknowns) using the graphing, substitution, and elimination methods. It also gives the students tips on choosing the most convenient method to solve a system of linear equations. It demonstrates an innovative and creative teaching method by posing open-ended questions where students use critical thinking to choose the most convenient method and explain why. This resource could be used for instructional purposes for deeper learning in an Algebra course. A teacher could also use it for extra classroom practice, homework, or self-directed learning for students who missed school when the teacher taught the related lesson.

Mathematics (2019) Grade(s): 8

MA19.8.12

Solve systems of two linear equations in two variables by graphing and substitution.

UP:MA19.8.12

Vocabulary

  • System of linear equations
  • Point of intersection
  • One solution
  • No solution
  • Infinitely many solutions
  • Parallel lines
  • Slope-intercept form of a linear equation
  • Standard form of a linear equation

Knowledge

Students know:
  • The properties of operations and equality and their appropriate application.
  • Graphing techniques for linear equations (using points, using slope-intercept form, using technology).
  • Substitution techniques for algebraically finding the solution to a system of linear equations.

Skills

Students are able to:
  • generate a table from an equation.
  • Graph linear equations.
  • Identify the ordered pair for the point of intersection.
  • Explain the meaning of the point of intersection (or lack of intersection point) in context.
  • Solve a system algebraically using substitution when both equations are written in slope-intercept form or one is written in standard form and the other in slope-intercept form.

Understanding

Students understand that:
  • any point on a line when substituted into the equation of the line, makes the equation true and therefore, the intersection point of two lines must make both equations true.
  • Graphs and equations of linear relationships are different representations of the same relationships, but reveal different information useful in solving problems, and allow different solution strategies leading to the same solutions.
Mathematics (2019) Grade(s): 8 - Grade 8 Accelerated

MA19.8A.9

Solve systems of two linear equations in two variables by graphing and substitution.

UP:MA19.8A.9

Vocabulary

  • System of linear equations
  • point of intersection
  • one solution
  • no solution
  • Infinitely many solutions
  • parallel lines
  • Slope-intercept form of a linear equation
  • Standard form of a linear equation

Knowledge

Students know:
  • The properties of operations and equality and their appropriate application.
  • Graphing techniques for linear equations (using points, using slope-intercept form, using technology).
  • Substitution techniques for algebraically finding the solution to a system of linear equations.

Skills

Students are able to:
  • generate a table from an equation.
  • Graph linear equations.
  • Identify the ordered pair for the point of intersection.
  • Explain the meaning of the point of intersection ( or lack of intersection point) in context.
  • Solve a system algebraically using substitution when both equations are written in slope-intercept form or one is written in standard form and the other in slope-intercept form.

Understanding

Students understand that:
  • Any point on a line when substituted into the equation of the line, makes the equation true and therefore, the intersection point of two lines must make both equations true,
  • Graphs and equations of linear relationships are different representations of the same relationships, but reveal different information useful in solving problems, and allow different solution strategies leading to the same solutions.

CR Resource Type

Informational Material

Resource Provider

LibreTexts Libraries, UC Davis

License Type

Attribution

Accessibility

Text Resources: Content is organized under headings and subheadings
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