CurriculumGrade 9Mathematics

Solving Quadratic Equations by Factoring

Aligned to A-REI.B.4 — Common Core State Standards for Mathematics.

What this lesson teaches

A quadratic equals zero when either factor equals zero (the Zero Product Property). Factor, set each factor to 0, and solve.

Worked example

x² + 5x + 6 = 0 → (x+2)(x+3) = 0 → x = −2 or x = −3.

Practice questions

  1. Solve x² − 7x + 12 = 0.
  2. Solve x² − 9 = 0.
  3. Why does the Zero Product Property work?

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Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.

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En español

Resolución de Ecuaciones Cuadráticas por Factorización

Una ecuación cuadrática es igual a cero cuando cualquiera de sus factores es igual a cero (Propiedad del Producto Nulo). Factoriza, iguala cada factor a 0 y resuelve.

Ejemplo: x² + 5x + 6 = 0 → (x+2)(x+3) = 0 → x = −2 o x = −3.

More Algebra lessons

Solving Linear Equations and InequalitiesA-REI.B.3Parts of an ExpressionA-SSE.A.1Rewriting by StructureA-SSE.A.2Equivalent Forms of ExpressionsA-SSE.B.3Operations with PolynomialsA-APR.A.1Zeros of PolynomialsA-APR.B.3

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