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Ch. 3 - Polynomial and Rational Functions
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook
Chapter 4, Problem 46

Graph each polynomial function. Factor first if the polynomial is not in factored form. ƒ(x)=x4+3x3-3x2-11x-6

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Start by writing down the polynomial function: \(f(x) = x^4 + 3x^3 - 3x^2 - 11x - 6\).
Attempt to factor the polynomial by looking for rational roots using the Rational Root Theorem. Possible roots are factors of the constant term \(-6\) divided by factors of the leading coefficient \(1\), so test \(\pm1, \pm2, \pm3, \pm6\).
Use synthetic division or polynomial division to test each possible root. When you find a root \(r\), factor out \((x - r)\) from the polynomial.
Continue factoring the resulting polynomial (which will be of lower degree) by repeating the process until the polynomial is fully factored into linear and/or quadratic factors.
Once factored, use the factored form to identify the zeros of the function and their multiplicities, then plot these points on the graph. Use the degree and leading coefficient to determine the end behavior of the graph.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Polynomial Factoring

Factoring a polynomial involves rewriting it as a product of simpler polynomials, which helps identify its roots and simplifies graphing. For higher-degree polynomials, techniques like synthetic division, grouping, or the Rational Root Theorem are often used to find factors.
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Finding Roots of Polynomials

Roots or zeros of a polynomial are the values of x that make the function equal to zero. These points correspond to x-intercepts on the graph and are critical for sketching the polynomial's shape and behavior.
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Graphing Polynomial Functions

Graphing involves plotting key points such as roots, end behavior, and turning points. Understanding the degree and leading coefficient helps predict the end behavior, while factoring reveals intercepts, enabling an accurate sketch of the polynomial.
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