In Exercises 39–52, find all zeros of the polynomial function or solve the given polynomial equation. Use the Rational Zero Theorem, Descartes's Rule of Signs, and possibly the graph of the polynomial function shown by a graphing utility as an aid in obtaining the first zero or the first root. 2x3−x2−9x−4=0
Table of contents
- 0. Review of Algebra4h 18m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations1h 43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 5m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 22m
- 10. Combinatorics & Probability1h 45m
4. Polynomial Functions
Zeros of Polynomial Functions
Problem 51
Textbook Question
For each polynomial function, find all zeros and their multiplicities.
Verified step by step guidance1
Start by identifying the factors of the polynomial function: \(f(x) = (x^2 + x - 2)^5 (x - 1 + \sqrt{3})^2\).
Find the zeros of the first factor \(x^2 + x - 2\) by solving the quadratic equation \(x^2 + x - 2 = 0\). Use factoring, completing the square, or the quadratic formula.
Once you find the roots of \(x^2 + x - 2 = 0\), note that each root has a multiplicity of 5 because the entire quadratic factor is raised to the 5th power.
Next, find the zero of the second factor \(x - 1 + \sqrt{3} = 0\) by isolating \(x\), which gives \(x = 1 - \sqrt{3}\). This zero has a multiplicity of 2 since the factor is squared.
List all zeros found along with their multiplicities: the roots from the quadratic factor each with multiplicity 5, and the root from the linear factor with multiplicity 2.
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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 that make the polynomial equal to zero. Finding zeros involves solving the equation f(x) = 0, which can be done by factoring or using other algebraic methods. Each zero corresponds to a root of the polynomial.
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Multiplicity of Zeros
Multiplicity refers to how many 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.
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Factoring and Solving Quadratic Expressions
Factoring quadratic expressions like x^2 + x - 2 helps find zeros by rewriting the polynomial as a product of linear factors. Solving these factors set to zero gives the roots. Recognizing and factoring quadratics is essential for breaking down complex polynomials.
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