Finding the Best Buy : Graphing Equations

• Mini-unit that reinforces learned concepts of algebraic equations and graphing.

• Grade Level: 8th grade or Pre-Algebra

• Methods of instruction: - Whole group- Small group- Individual

• 2 – 3 49-minute class periods

• Objective: Students will be able to apply their knowledge of solving equations to

determine the best buy in a given scenario. Students will also justify their findings by creating a graph.

Common Core Standards

1) Make sense of problems and persevere in solving them.

2) Reason abstractly and quantitatively.

3) Construct viable arguments and critique the reasoning of others.

4) Model with mathematics.

5) Use appropriate tools strategically.

6) Attend to precision.

Day 1 Review

• - Bell ringer- student led• - Vocabulary review- flash card/definition activity

variable constant slope functionequation solution

trend x-axis y-axis

• - Problem solving strategies: create a table• - Graph review: Creating and analyzing What does the x-axis represent?

What does the y-axis represent? What type of graph best fits the equation?

Day 1

You have a babysitting job for a neighbor. You agree on a base payment of $10 for each babysitting job, and then $2.00 additional for each hour worked.

a) How much will you make each hour babysitting up to 8 hours?

b) Write the equation you will use to solve this problem. Identify the constant and the variable.

c) Create a table of answers.

d) Make a graph.

Day 2

• Hook: cell phone plans My personal plan: Unlimited usage, calls & text - $129.99

call usage 400 minutes

Am I getting ripped off???

Day 2

• Investigate and discuss.

• Present two other phone plans.

• Students will work in pairs to create equations based on the given plans.

• Analyze plans to find the best cost for the teacher usage of 400 minutes.

• Try to sell the teacher on which plan would be best by creating graphical representation.

Day 3 Independent

• Quick review about previous day.

• Independent assessment: Rent-a-car activity.

• Explain components of activity.

• Emphasize that a large portion of the assessment is the ability to communicate mathematics effectively.

• Can they apply what they have learned?