CurriculumGrade 9Mathematics

Rewriting by Structure

Aligned to A-SSE.A.2 — Common Core State Standards for Mathematics.

What this lesson teaches

Recognizing a pattern lets you rewrite an expression quickly. A difference of squares a^2 − b^2 always factors as (a + b)(a − b).

Worked example

Factor x^2 − 49. Since 49 = 7^2, this is a difference of squares: x^2 − 7^2 = (x + 7)(x − 7).

Practice questions

  1. Factor x^2 − 25.
  2. Factor 9x^2 − 16.
  3. Rewrite x^4 − 1 as a product of factors.

Watch the lesson

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

Reescribir por Estructura

Reconocer un patrón te permite reescribir una expresión rápidamente. Una diferencia de cuadrados a^2 − b^2 siempre se factoriza como (a + b)(a − b).

Ejemplo: Factoriza x^2 − 49. Como 49 = 7^2, esto es una diferencia de cuadrados: x^2 − 7^2 = (x + 7)(x − 7).

More Algebra lessons

Solving Linear Equations and InequalitiesA-REI.B.3Solving Quadratic Equations by FactoringA-REI.B.4Parts of an ExpressionA-SSE.A.1Equivalent Forms of ExpressionsA-SSE.B.3Operations with PolynomialsA-APR.A.1Zeros of PolynomialsA-APR.B.3

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