Solving One-Variable Equations

Lesson 10

Math

Unit 2

8th Grade

Lesson 10 of 12

Objective


Use equations to model a business plan and determine the break-even point.

Common Core Standards


Core Standards

  • 8.EE.C.7 — Solve linear equations in one variable.

Foundational Standards

  • 7.EE.B.4

Criteria for Success


  1. De-contextualize a situation to represent it algebraically, and re-contextualize to interpret the solution in context of the problem (MP.2).
  2. Write and solve equations to represent a real-world business plan (MP.4).

Tips for Teachers


There is only one Anchor Problem for this lesson, however, it is longer than usual. It can be done with the whole class, or students can tackle it in small groups. The Target Task has students create their own problem similar to the Anchor Problem. The Problem Set Guidance includes a variety of resources that involve real-world applications.

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Anchor Problems

25-30 minutes


Corey and Akila are making small wooden tables to sell at the school fair. They have some fixed costs and some variable costs. The fixed costs come to $160 and include things that only need to be purchased once, like an electric saw, measuring tools, and a work station. The variable costs come to $3.50 for each table and include the wood, nails, and glue needed for each table. Corey and Akila plan to sell each table for $10.

a.   Fill in the chart below for different numbers of tables sold at the school fair.

# Tables Sold Total Fixed Costs Total Variable Costs Total Costs Money Earned from Sales Total Profit or Loss

 

         

 

         

 

         

 

         

b.   Write an equation to represent this situation. Explain what each part of your equation represents. 

c.   How many tables do Corey and Akila need to sell to break even?

d.   How many tables do Corey and Akila need to sell to make a profit of $150?

Guiding Questions

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Student Response

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Problem Set

15-20 minutes


Give your students more opportunities to practice the skills in this lesson with a downloadable problem set aligned to the daily objective.

Target Task

5-10 minutes


Create your own business model, similar to Anchor Problem 1. 

  • What are you selling?
  • What are your fixed costs? Your variable costs?
  • How much will you sell each item for?
  • How many do you need to sell to break even? 

Show all of your work clearly and include an equation in your answer.

Student Response

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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.

Next

Solve and graph inequalities with variables on one side of the inequality (optional).

Lesson 11
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Lesson Map

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

Topic A: Simplifying Expressions and Verifying Solutions

Topic B: Analyzing and Solving Equations in One Variable

Topic C: Analyzing and Solving Inequalities in One Variable

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