CCSS.Math.Content.8.EE.C.7
The standard
Solve linear equations in one variable.
Common Core State Standards for Mathematics · Expressions and Equations
What this standard means
Students need to solve one-variable linear equations, including equations with variables on both sides, parentheses, fractions, and decimals. They should use inverse operations, combine like terms, and keep both sides balanced. They also need to recognize when an equation has one solution, no solution, or infinitely many solutions.
Mastery looks like clean, logical steps with the solution checked in the original equation. Students often get stuck distributing negatives, clearing fractions, moving variable terms, and telling the difference between a false statement like 3 = 5 and a true statement like 4 = 4.
Ways to teach it
- Use algebra tiles or paper balance mats to solve 3x + 2 = x + 10, then record each move as an equation step.
- Ask students to explain in writing why 2(x + 3) = 2x + 6 has infinitely many solutions.
- Give three equations, one with one solution, one with no solution, and one with infinitely many solutions, and have students classify them.
- Have students write and solve an equation for a phone plan with a fixed fee plus a per-gigabyte charge.
Plan a lesson for CCSS.Math.Content.8.EE.C.7
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Related standards
- CCSS.Math.Content.HSA-REI.B
Solve equations and inequalities in one variable
- CCSS.Math.Content.HSA-REI.B.4
Solve quadratic equations in one variable.
- CCSS.Math.Content.8.EE.C.8c
Solve real-world and mathematical problems leading to two 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.