Extension Activities: Energy and Engineering Trends: Systems of Equations Duration: 90 min Standards: HSA.CED.A.1 HSA.CED.A.2 HSA.CED.F-IF.4 HSA.CED.A-REI.6 HSA.CED.A-REI.11 Overview: Students must determine ‘which is the better lightbulb?”. In the previous lesson they determined energy efficiency/cost efficiency. In this lesson, the purchase prices of the lightbulbs are introduced and students must answer the same question as well as a follow up question, using systems of equations to solve. Algebra 1 Materials: Worksheet Graphing calculator (TI-84) Pencils/Pens Graphing Paper Extension Activities: Have students research different energy efficient appliances. Vary energy usage depending on weekday/weekend to challenge higher-level learners.

Procedure: Teacher Tips: Students will be introduced to the purchase price of each lightbulb and asked again, “Which lightbulb should I buy?” After a class discussion, they will then be asked “How long will it take for me to start having cost-benefits from my purchase? Students will be instructed on systems of equations and the concept of break-even point. Students will solve the initial class question by graphing and solving systems of equations for each lightbulb pair. Teacher Tips: Have higher order thinking questions prepared ahead of time to guide discussion.