Extraneous Solutions

Learning Resource Type

Classroom Resource

Subject Area

Mathematics

Grade(s)

9, 10, 11, 12

Overview

Extraneous solutions are values that you may get when solving equations that aren't really solutions to the equation. This video will explain how and why you can arrive at extraneous solutions, by understanding the logic behind the process of solving equations. There is an additional video to explain this concept, as well as two question sets.

Mathematics (2019) Grade(s): 09-12 - Algebra I with Probability

MA19.A1.8

Explain why extraneous solutions to an equation involving absolute values may arise and how to check to be sure that a candidate solution satisfies an equation.

UP:MA19.A1.8

Vocabulary

  • Absolute Value
  • Equations
  • Extraneous solution

Knowledge

Students know:
  • Algebraic rules for manipulating absolute value equations.
  • Conditions under which a solution is considered extraneous.

Skills

Students are able to:
  • Accurately rearrange absolute value equations to produce a set of values to test against the conditions of the original situation and equation, and determine whether or not the value is a solution.
  • Explain with mathematical reasoning from the context (when appropriate) why a particular solution is or is not extraneous.

Understanding

Students understand that:
  • Values which arise from solving absolute value equations may not satisfy the original equation.
  • Values which arise from solving the equations may not exist due to considerations in the context.

CR Resource Type

Audio/Video

Resource Provider

Khan Academy

License Type

Custom

Accessibility

Video resources: includes closed captioning or subtitles
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