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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 52

For each polynomial function, find all zeros and their multiplicities. ƒ(x)=(2x27x+3)3(x25)ƒ(x)=(2x^2-7x+3)^3(x-2-\(\sqrt\)5)

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Identify the factors of the polynomial function: \(f(x) = (2x^2 - 7x + 3)^3 (x - 2 - \sqrt{5})\). The zeros come from setting each factor equal to zero.
Find the zeros of the quadratic factor \$2x^2 - 7x + 3\( by using the quadratic formula: \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\), where \)a=2\(, \)b=-7\(, and \)c=3$.
Calculate the discriminant \(\Delta = b^2 - 4ac\) to determine the nature of the roots of the quadratic. Then substitute into the quadratic formula to find the two zeros.
Note that each zero from the quadratic factor has multiplicity 3 because the entire quadratic is raised to the third power.
Find the zero from the linear factor \(x - 2 - \sqrt{5} = 0\), which gives \(x = 2 + \sqrt{5}\), and note that this zero has multiplicity 1 since the factor is to the first power.

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Key Concepts

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

Polynomial Zeros

Zeros of a polynomial are the values of x for which the polynomial equals zero. Finding zeros involves solving the equation f(x) = 0, which may require factoring or using formulas. These zeros represent the roots or x-intercepts of the polynomial function.
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Multiplicity of Zeros

Multiplicity refers to the number of times a particular zero appears as a factor in the polynomial. If a factor is raised to a power n, the zero associated with that factor has multiplicity n. Multiplicity affects the graph's behavior at the zero, such as whether it crosses or touches the x-axis.
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Factoring and Solving Quadratic Expressions

Factoring quadratic expressions like 2x² - 7x + 3 helps find zeros by rewriting the polynomial as a product of linear factors. When factoring is difficult, the quadratic formula can be used. This step is essential to break down complex polynomials into simpler parts to identify zeros.
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