Lesson 3: Solving Systems by Substitution

• How do we solve a system by substitution?
• Which equation should we solve first?
• What do we substitute?
• How do we find both variables?

Substitution, isolate, substitute, solve, solution, ordered pair

CCSS.MATH.8.EE.C.8

Description: Students solve one equation for a variable, then substitute that expression into the other equation. This creates one equation with one variable, which they solve, then find the other variable. Step-by-step guides help them follow the process. Purpose: To develop procedural fluency in an algebraic method for solving systems. DOK Level: 2-3 (Application)

• Step-by-step cards: Provide substitution steps in order with visuals
• For struggling learners: Use systems where one equation is already solved for a variable
• For advanced learners: Solve systems requiring manipulation of both equations
• Color-coding: Use different colors for each variable

• Observation: Do students follow substitution steps correctly?

• Worksheet: Solve 4 systems using substitution

• Step-by-step task: Solve with all steps shown

• Verification: Check solutions in both equations

• Substitution method step-by-step guides

• Practice worksheets (varying difficulty)

• Verification worksheets

• Anchor chart for substitution steps

• Resource: Khan Academy "Solving Systems by Substitution" (adapted)