Chapter 0: Problem 29
Completely factor the polynomial. $$ 2 x^{3}-3 x^{2}+4 x-6 $$
Short Answer
Expert verified
The completely factored form of the polynomial \(2x^{3}-3x^{2}+4x-6\) is \((x - 1)(2x + 3)(x - 2)\)
Step by step solution
01
Identify Polynomial and its Degree
The given polynomial is \(2x^{3}-3x^{2}+4x-6\) and its degree is 3.
02
Find Potential Rational Roots
The potential rational roots of a polynomial can be found using the rational root theorem. According to this theorem, if a polynomial has a rational root \(p / q\) then p is a factor of the constant term and q is a factor of the leading coefficient i.e; p is a factor of -6 (±1, ±2, ±3, ±6) and q is a factor of 2 (±1, ±2). Therefore, the potential rational roots of the given polynomial are \(±1, ±2, ±3, ±6, ±0.5, ±1.5, ±3\).
03
Substitute Potential Roots
Substitute the potential roots into the polynomial until the output equals zero. Taking \(x = 1\) we find that the polynomial equals zero. So, \(x = 1\) is a root of the polynomial.
04
Perform Polynomial Division
Divide the polynomial \(2x^{3}-3x^{2}+4x-6\) by \(x-1\) using polynomial long division. The result is \(2x^2 - x - 6\).
05
Factor the Quadratic Result
The quadratic \(2x^{2} - x - 6\) can be factored into \((2x + 3) (x - 2)\). Hence, the complete factor of the given polynomial is \((x - 1)(2x + 3)(x - 2)\).
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Rational Root Theorem
The Rational Root Theorem is a useful tool when we need to factor polynomials. It gives us a list of possible rational roots or zeroes for a given polynomial. These roots can be numbers that, if plugged into the polynomial, would make it equal to zero.
To apply this theorem, follow these steps:
This results in potential roots of ±1, ±2, ±3, ±6, ±0.5, ±1.5, and ±3.
To apply this theorem, follow these steps:
- Identify the constant term of the polynomial, which is the last number (here, it is -6).
- Identify the leading coefficient, which is the coefficient of the highest degree term (here, it is 2).
- Factors of the constant term (-6) include ±1, ±2, ±3, and ±6.
- Factors of the leading coefficient (2) include ±1 and ±2.
This results in potential roots of ±1, ±2, ±3, ±6, ±0.5, ±1.5, and ±3.
Polynomial Division
Once we have a root from the Rational Root Theorem (in this case, \( x=1 \)), we use polynomial division to simplify the polynomial further. Polynomial division is similar to long division used with numbers but is applied to polynomials.
Here's how it works:
Here's how it works:
- Set the root (here \( x-1 \)) as the divisor.
- Divide the original polynomial \( 2x^3 - 3x^2 + 4x - 6 \) by \( x-1 \).
- Perform the division step-by-step, starting with the highest degree term.
- The result will be a simplified polynomial, after which the remainder should be zero if the division was exact.
Quadratic Factoring
After polynomial division, what remains might be a quadratic expression. In this exercise, after dividing \( 2x^3 - 3x^2 + 4x - 6 \) by \( x-1 \), we get \( 2x^2 - x - 6 \).
Factoring a quadratic polynomial involves finding two binomials that multiply to give the original quadratic.
Here's the approach:
Factoring a quadratic polynomial involves finding two binomials that multiply to give the original quadratic.
Here's the approach:
- Look for two numbers that multiply to the product of the quadratic's leading coefficient (2) and the constant term (-6), which is -12.
- These numbers also need to add up to the linear coefficient (-1).
- In this case, -3 and 4 work because \(-3 \times 4 = -12\) and \(-3 + 4 = 1\).
- Use these numbers to split the middle term, and then factor by grouping.
- The final factors of \( 2x^2 - x - 6 \) are \((2x + 3)\) and \((x - 2)\).