/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 74 Find a polynomial function that ... [FREE SOLUTION] | 91Ó°ÊÓ

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Find a polynomial function that has the given zeros. (There are many correct answers.) \(3,2+\sqrt{7}, 2-\sqrt{7}\)

Short Answer

Expert verified
The polynomial function with zeros \(3, 2+ \sqrt{7}\), \(2- \sqrt{7}\) is \(x^{3} - 7x^{2} + 13x - 9\) .

Step by step solution

01

Define the factors

The first step involves transforming the zeros of the polynomial into its factors. In general, if \(r\) is a zero of the polynomial, then \((x - r)\) is a factor of the polynomial. Therefore, the factors sourced from our zeros will be \((x - 3)\), \((x - (2 + \sqrt{7}))\) and \((x - (2 - \sqrt{7}))\) .
02

Simplify the factors

The second factor can be written as \( (x - 2 - \sqrt{7})\) and the third factor can be written as \( (x - 2 + \sqrt{7})\). Notice how these two are conjugates, and thus, their product will result in a difference of squares.
03

Multiply the factors

This step involves multiplying all of the factors together to find the polynomial function. Thus, the polynomial will be \((x - 3) * (x - 2 - \sqrt{7})*(x - 2 + \sqrt{7})\).
04

Simplify the polynomial

Since the last two factors are conjugates, we can simplify them as the difference of squares. The polynomial then simplifies to \( (x - 3) * [(x - 2)^{2} - (\sqrt{7})^{2}]\) . Expanding this expression we get \( (x - 3) * (x^{2} - 4x + 4 - 7)\). Next, simplify the expression to get \( (x - 3) * (x^{2} - 4x - 3)\). Distribute the \( (x - 3)\) to get the final polynomial \( x^{3} - 7x^{2} + 13x - 9\) .

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Factoring Polynomials
Factoring polynomials is a critical process in algebra that involves breaking down a polynomial into simpler components, or 'factors', that when multiplied together, give back the original polynomial. It's like taking a complex puzzle and finding the individual pieces that fit together to create the overall picture.

For example, when given zeros of a polynomial, such as in our exercise with zeros 3, 2 + \(\t{1}\), and 2 - \(\sqrt{7}\), we can convert these zeros into factors by subtracting each zero from the variable x, giving us (x - 3), (x - (2 + \(\sqrt{7}\))), and (x - (2 - \(\sqrt{7}\))). The goal is to transform these into a multiplied form that represents the polynomial.

Understanding how to factor is essential for solving equations, simplifying expressions, and even finding zeros of functions, as the ability to manipulate and rewrite polynomials paves the way to unveil the intricate relationships among numbers and variables.
Difference of Squares
The concept of the difference of squares is a special product formula in algebra that states for any two terms a and b, \(a^2 - b^2\) can be factored into \((a + b)(a - b)\). It is used frequently to simplify expressions involving squares and is particularly useful when dealing with polynomial roots that are conjugate pairs.

When we multiply the factors obtained from the zeros (2 + \(\sqrt{7}\)) and (2 - \(\sqrt{7}\)), we utilize the difference of squares property. These factors are conjugates, so their product simplifies to \((x - 2)^2 - (\sqrt{7})^2\), which further simplifies to \(x^2 - 4x + 4 - 7\). This concept allows us to transform a seemingly complicated polynomial multiplication into a much simpler form. Recognizing a difference of squares situation is a valuable tool in a math student's toolkit.
Polynomial Roots
Polynomial roots, also known as zeros, are the values for which the polynomial function equals zero. These are the solutions to the equation formed by setting the polynomial equal to zero. In essence, finding the roots is like discovering the x-intercepts or the exact points where the graph of the polynomial crosses the x-axis.

Working with roots is indispensable, as they reveal a great deal about the behavior of a polynomial function. A polynomial of degree n generally has n roots, which could be real, complex, or repeated. The zeros given in our exercise, 3, 2 + \(\sqrt{7}\), and 2 - \(\sqrt{7}\), are the starting points for building the factors of the polynomial and ultimately the polynomial itself. This optimization for easier understanding helps in recognizing patterns and using rules and properties efficiently to solve for these critical points.
Conjugate Pairs
In complex algebra, a pair of binomials of the form a + b and a - b are known as conjugate pairs. They are useful for rationalizing denominators containing radicals as well as for factoring certain types of polynomials. A remarkable property of conjugate pairs is that, when multiplied, they eliminate the radical portion, resulting in a difference of squares.

From our exercise, the zeros 2 + \(\sqrt{7}\) and 2 - \(\sqrt{7}\) are conjugate pairs. When factoring polynomials, recognizing conjugate pairs is invaluable since their product will be a polynomial without radicals, which simplifies the expression. This ability to pair and simplify is a fundamental skill in advancing one’s algebra proficiency. Understanding the role of conjugate pairs within the broader topic of polynomial functions will make factoring an easier and more intuitive process.

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Most popular questions from this chapter

Use the zero or root feature of a graphing utility to approximate (accurate to the nearest thousandth) the zeros of the function, (b) determine one of the exact zeros and use synthetic division to verify your result, and (c) factor the polynomial completely. $$g(x)=6 x^{4}-11 x^{3}-51 x^{2}+99 x-27$$

A page that is \(x\) inches wide and \(y\) inches high contains 30 square inches of print (see figure). The margins at the top and bottom are 2 inches deep and the margins on each side are 1 inch wide. (a) Show that the total area \(A\) of the page is given by $$A=\frac{2 x(2 x+11)}{x-2}$$ (b) Determine the domain of the function based on the physical constraints of the problem. (c) Use a graphing utility to graph the area function and approximate the page size such that the minimum amount of paper will be used. Verify your answer numerically using the table feature of the graphing utility.

Let \(f(x)=14 x-3\) and \(g(x)=8 x^{2} .\) Find the indicated value. \((f \circ g)(-1)\)

Divide using long division. $$\left(2 x^{4}+x^{2}-11\right) \div\left(x^{2}+5\right)$$

The numbers of employees \(E\) (in thousands) in education and health services in the United States from 1960 through 2013 are approximated by \(E=-0.088 t^{3}+10.77 t^{2}+14.6 t+3197\) \(0 \leq t \leq 53,\) where \(t\) is the year, with \(t=0\) corresponding to \(1960. (a) Use a graphing utility to graph the model over the domain. (b) Estimate the number of employees in education and health services in \)1960 .\( Use the Remainder Theorem to estimate the number in \)2010 .$ (c) Is this a good model for making predictions in future years? Explain.

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