CurriculumGrade 9Mathematics

Zeros of Polynomials

Aligned to A-APR.B.3 — Common Core State Standards for Mathematics.

What this lesson teaches

The zeros of a polynomial are the x-values where it equals 0 — they are the x-intercepts of its graph. Factor, set each factor equal to 0, and solve to find them.

Worked example

Find the zeros of y = (x − 1)(x + 4). Set each factor to 0: x − 1 = 0 gives x = 1, and x + 4 = 0 gives x = −4. The graph crosses the x-axis at (1, 0) and (−4, 0).

Practice questions

  1. Find the zeros of y = (x + 2)(x − 6).
  2. Find the zeros of y = x(x − 3).
  3. Factor y = x^2 − x − 12 and give its zeros.

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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

Ceros de Polinomios

Los ceros de un polinomio son los valores de x donde vale 0: son las intersecciones con el eje x de su gráfica. Factoriza, iguala cada factor a 0 y resuelve para hallarlos.

Ejemplo: Halla los ceros de y = (x − 1)(x + 4). Iguala cada factor a 0: x − 1 = 0 da x = 1, y x + 4 = 0 da x = −4. La gráfica corta el eje x en (1, 0) y (−4, 0).

More Algebra lessons

Solving Linear Equations and InequalitiesA-REI.B.3Solving Quadratic Equations by FactoringA-REI.B.4Parts of an ExpressionA-SSE.A.1Rewriting by StructureA-SSE.A.2Equivalent Forms of ExpressionsA-SSE.B.3Operations with PolynomialsA-APR.A.1

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