Rational and Radical Functions

Lesson 15

Math

Unit 4

11th Grade

Lesson 15 of 18

Objective


Solve radical equations and identify extraneous solutions. 

Common Core Standards


Core Standards

  • A.REI.A.2 — Solve simple rational and radical equations in one variable, and give examples showing how extraneous solutions may arise.

Foundational Standards

  • A.REI.A.1

Criteria for Success


  1. Describe how a solution could be extraneous. 
  2. Explain how, when a radical equation has a variable outside of the radical, the result is a polynomial equation that must be solved. 
  3. Determine extraneous solutions from complex radical equations.
  4. Solve rational exponent equations either by converting to radical equations or by working with the rational exponents in their current form. 
Fishtank Plus

Unlock features to optimize your prep time, plan engaging lessons, and monitor student progress.

Anchor Problems


Problem 1

Solve the following equation: 
 

$${\sqrt{-3x-5}-2=x+1}$$

 

Guiding Questions

Create a free account or sign in to access the Guiding Questions for this Anchor Problem.

Problem 2

Solve the following equation: 

 

$${(x-2)^{2\over3}=4}$$

 

Guiding Questions

Create a free account or sign in to access the Guiding Questions for this Anchor Problem.

Target Task


Below are three answers to the problem $${{{{\sqrt{x-2}=2-x}}}}$$. Which answer is correct? Explain your reasoning. 

 

Answer #1 Answer #2 Answer #3

$${{{{\sqrt{x-2}=2-x}}}}$$

$${{x-2=4-4x+x^2}}$$

$${{0=6-5x+x^2}}$$

$${{x^2-5x+6=0}}$$

$${{(x-2)(x-3)=0}}$$

 

Solution: $${{x=2}}$$ and $${{x=3}}$$

$${{{{\sqrt{x-2}=2-x}}}}$$

$${x-2=4+x^2}$$

$${0=6-x+x^2}$$

$${x^2-x+6=0}$$

$${(x-3)(x+2)=0}$$

 

Solution: $${{x=3}}$$ and $${x=-2}$$

$${{{{\sqrt{x-2}=2-x}}}}$$

$${{x-2=4-4x+x^2}}$$

$${{0=6-5x+x^2}}$$

$${{x^2-5x+6=0}}$$

$${{(x-2)(x-3)=0}}$$

 

Solution: $${{x=2}}$$

 

Additional Practice


The following resources include problems and activities aligned to the objective of the lesson that can be used for additional practice or to create your own problem set.

icon/arrow/right/large copy

Lesson 14

icon/arrow/right/large

Lesson 16

Lesson Map

A7CB09C2-D12F-4F55-80DB-37298FF0A765

Topic A: Introduction to Rational and Radical Functions and Expressions

Topic B: Features of Rational Functions and Graphing Rational Functions

Topic C: Solve Rational and Radical Equations and Model with Rational Functions

Request a Demo

See all of the features of Fishtank in action and begin the conversation about adoption.

Learn more about Fishtank Learning School Adoption.

Contact Information

School Information

What courses are you interested in?

ELA

Math

Are you interested in onboarding professional learning for your teachers and instructional leaders?

Yes

No

Any other information you would like to provide about your school?

Effective Instruction Made Easy

Effective Instruction Made Easy

Access rigorous, relevant, and adaptable math lesson plans for free