/*! 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 \(k\) so that \(4 x+3\) is ... [FREE SOLUTION] | 91Ó°ÊÓ

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Find \(k\) so that \(4 x+3\) is a factor of $$20 x^{3}+23 x^{2}-10 x+k$$

Short Answer

Expert verified
The value of \(k\) that makes \(4x+3\) a factor of the polynomial \(20x^3+23x^2-10x+k\) is \(-9\).

Step by step solution

01

Apply the Remainder Theorem

According to the Remainder Theorem, we will substitute the root of the divisor \(4x+3 = 0\) into the polynomial. To find the root, we set the divisor equal to zero and solve for \(x\). Thus, for \(4x+3=0\), solving for \(x\), we get \(x = -\frac{3}{4}\). Now substitute \(x=-\frac{3}{4}\) into \(20x^3+23x^2-10x+k\) which results in: \(20(-\frac{3}{4})^3+23(-\frac{3}{4})^2-10(-\frac{3}{4})+k\).
02

Simplify

Calculating the above results in: \(-\frac{135}{8}-\frac{207}{16}+ \frac{15}{2} + k\). However, for it to be divisible by \(4x+3\), the result must be \(0\). So set the expression equal to \(0\). Thus, it becomes \(k = \frac{135}{8}+\frac{207}{16}-\frac{15}{2}\).
03

Solve for k

Adding \(\frac{135}{8},\frac{207}{16},-\frac{15}{2}\) simplifies to \(k = -9\). So the required value for \(k\) is \(-9\) which makes \(4x+3\) a factor of the polynomial \(20x^3+23x^2-10x+k\).

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Key Concepts

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

Polynomial Long Division
Polynomial long division is a process similar to long division with numbers, but instead, it's used for dividing polynomials. To break down complex polynomial expressions, long division can simplify the understanding of a polynomial's behavior, especially when finding factors or simplifying expressions.
The process involves dividing the polynomial's leading term by the leading term of the divisor and multiplying the entire divisor by that quotient. This product is then subtracted from the polynomial, and the process is repeated for the remaining polynomial terms. The end result consists of a quotient and possibly a remainder. If a polynomial divides another polynomial with zero remainder, then the former is a factor of the latter. An important use case, as shown in the exercise, is to determine specific values that can make a polynomial divisible by another.
Factoring Polynomials
Factoring polynomials is a critical concept in algebra that involves breaking down a polynomial into a product of its factors. These factors are simpler polynomials whose multiplication results in the original polynomial.
Strategies for factoring polynomials include finding the greatest common factor, using the difference of squares rule, sum and difference of cubes, or quadratic expressions. For more complex polynomials, factoring by grouping or applying special formulas might be needed. Factoring is not only a crucial step in solving polynomial equations but also in simplifying expressions and understanding the behavior of graphs. For the given exercise, understanding this concept helps us utilize the Remainder Theorem effectively, since a zero remainder after division indicates that the divisor is indeed a factor of the polynomial.
Synthetic Division
Synthetic division is an alternative to polynomial long division and is particularly useful when dividing by a linear factor. It's a shorthand method that allows for a quicker and more efficient calculation.
To perform synthetic division, you create a table using the coefficients of the polynomial to be divided, excluding any zero coefficients for terms that are missing. Then you bring down the leading coefficient and proceed to multiply and add according to the synthetic division algorithm, which closely mirrors the steps taken in long division. The result of synthetic division is the quotient and remainder, similar to long division. This method is especially convenient when applying the Remainder Theorem, as seen in our exercise, for it swiftly provides the remainder of the polynomial when divided by a linear factor, like the divisor used in our problem.

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Most popular questions from this chapter

Write the equation of each parabola in standard form. Each group member should consult an almanac, newspaper, magazine, or the Internet to find data that initially increase and then decrease, or vice versa, and therefore can be modeled by a quadratic function. Group members should select the two sets of data that are most interesting and relevant. For each data set selected, a. Use the quadratic regression feature of a graphing utility to find the quadratic function that best fits the data. b. Use the equation of the quadratic function to make a prediction from the data. What circumstances might affect the accuracy of your prediction? c. Use the equation of the quadratic function to write and solve a problem involving maximizing or minimizing the function.

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