CCSS.Math.Content.HSA-REI.B.4
The standard
Solve quadratic equations in one variable.
Common Core State Standards for Mathematics
What this standard means
Students need to solve one-variable quadratic equations by choosing a workable method: factoring, taking square roots, completing the square, or using the quadratic formula. They should connect each method to the structure of the equation, not just memorize steps.
Mastery looks like accurate solutions, including two solutions, one solution, or no real solutions, with checks by substitution or graphing. Students often get stuck choosing a method, handling signs in the quadratic formula, forgetting the plus-or-minus, or thinking every quadratic factors nicely.
Ways to teach it
- Hands-on activity: Give students equation cards and method cards, then have them match each equation to the fastest solving method and justify it.
- Discussion or writing prompt: Ask, “How can you tell before solving whether factoring is a good choice?” and have students defend one example.
- Quick assessment: Give three equations, one factorable, one square-root form, and one needing the formula, and ask for solutions plus method choice.
- Real-world connection: Use a ball height equation and ask when the ball hits the ground, then explain why only one solution makes sense.
Plan a lesson for CCSS.Math.Content.HSA-REI.B.4
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Related standards
- CCSS.Math.Content.HSA-REI.B
Solve equations and inequalities in one variable
- CCSS.Math.Content.8.EE.C.7
Solve linear equations in one variable.
- CCSS.Math.Content.HSA-REI.B.3
Solve linear equations and inequalities in one variable, including equations with coefficients represented by letters.
- CCSS.Math.Content.HSA-REI.C.7
Solve a simple system consisting of a linear equation and a quadratic equation in two variables algebraically and graphically.