CCSS.Math.Content.8.EE.C

CCSS.Math.Content.8.EE.C is a cluster heading. These are the individual standards under it.

• CCSS.Math.Content.8.EE.C.7

  Solve linear equations in one variable.

• CCSS.Math.Content.8.EE.C.7a

  Give examples of linear equations in one variable with one solution, infinitely many solutions, or no solutions. Show which of these possibilities is the case b...

• CCSS.Math.Content.8.EE.C.7b

  Solve linear equations with rational number coefficients, including equations whose solutions require expanding expressions using the distributive property and ...

• CCSS.Math.Content.8.EE.C.8

  Analyze and solve pairs of simultaneous linear equations.

• CCSS.Math.Content.8.EE.C.8a

  Understand that solutions to a system of two linear equations in two variables correspond to points of intersection of their graphs, because points of intersect...

• CCSS.Math.Content.8.EE.C.8b

  Solve systems of two linear equations in two variables algebraically, and estimate solutions by graphing the equations. Solve simple cases by inspection.

• CCSS.Math.Content.8.EE.C.8c

  Solve real-world and mathematical problems leading to two linear equations in two variables.

01

What Students Need to Do

Students solve linear equations with variables on one or both sides. They also solve pairs of linear equations and interpret the solution as the point that makes both equations true.

02

What Mastery Looks Like

Students solve multistep linear equations and identify equations with one solution, no solution, or infinitely many solutions. They solve systems by graphing or algebra and verify the ordered pair in both equations.

03

Common Misconceptions

Students may change one side of an equation without making the same change to the other side. They may confuse parallel lines with the same line, or treat an intersection estimate as an exact solution.

04

How to Assess It

Give students the equation 3(x - 2) = 2x + 5 and the system y = 2x - 1, y = -x + 5. Ask them to solve each and check their answers.

1. 01

   Use a balance scale and algebra tiles to model 2x + 3 = 11, then connect each physical move to an algebra step.

2. 02

   Ask students to explain how slopes and intercepts show whether two lines meet once, never meet, or represent the same line.

3. 03

   Run a card sort matching equations and systems to solutions, graphs, and labels for one, none, or infinitely many solutions.

4. 04

   Compare two phone plans with different starting fees and monthly costs, then find when both plans cost the same.

• CCSS.Math.Content.HSA-REI.C.6

  Solve systems of linear equations exactly and approximately (e.g., with graphs), focusing on pairs of linear equations in two variables.

• CCSS.Math.Content.HSA-REI.B.3

  Solve linear equations and inequalities in one variable, including equations with coefficients represented by letters.