CurriculumGrade 9Mathematics

Revealing Properties by Rewriting

Aligned to F-IF.C.8 — Common Core State Standards for Mathematics.

What this lesson teaches

Writing a quadratic in factored form reveals its zeros, while vertex form reveals its maximum or minimum. Choose the form that shows the property you want.

Worked example

Rewrite y = x^2 − 6x + 8 in factored form to find its zeros. It factors as (x − 2)(x − 4), so the zeros are x = 2 and x = 4.

Practice questions

  1. Factor y = x^2 + 5x + 6 and state its zeros.
  2. Factor y = x^2 − 16 and state its zeros.
  3. The form y = (x − 3)^2 + 1 shows a minimum. Give the vertex.

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

Revelar Propiedades al Reescribir

Escribir una cuadrática en forma factorizada revela sus ceros, mientras que la forma de vértice revela su máximo o mínimo. Elige la forma que muestre la propiedad que buscas.

Ejemplo: Reescribe y = x^2 − 6x + 8 en forma factorizada para hallar sus ceros. Se factoriza como (x − 2)(x − 4), así que los ceros son x = 2 y x = 4.

More Functions lessons

Interpreting Graphs of FunctionsF-IF.B.4What Is a Function?F-IF.A.1Evaluating FunctionsF-IF.A.2Sequences as FunctionsF-IF.A.3Domain in ContextF-IF.B.5Average Rate of ChangeF-IF.B.6

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