Math Problem Statement

Which of the following is a factor of x^3 - 5x^2 - 2x + 24, given that x - 3 is one of the linear factors?

Solution

The question asks which of the given options is a factor of the polynomial x35x22x+24x^3 - 5x^2 - 2x + 24, knowing that x3x - 3 is one of its linear factors.

Steps to solve:

  1. Given: One of the factors is x3x - 3, meaning that x=3x = 3 is a root of the polynomial.
  2. Polynomial Division: We can divide x35x22x+24x^3 - 5x^2 - 2x + 24 by x3x - 3 using either synthetic or long division to find the quotient, which will help us identify the remaining factors.

Let's start by dividing x35x22x+24x^3 - 5x^2 - 2x + 24 by x3x - 3.

Polynomial division of x35x22x+24x^3 - 5x^2 - 2x + 24 by x3x - 3:

  • Divide the leading term x3x^3 by xx, which gives x2x^2.
  • Multiply x2x^2 by x3x - 3, giving x33x2x^3 - 3x^2.
  • Subtract (x33x2)(x^3 - 3x^2) from x35x2x^3 - 5x^2, which results in 2x2-2x^2.
  • Divide 2x2-2x^2 by xx, which gives 2x-2x.
  • Multiply 2x-2x by x3x - 3, giving 2x2+6x-2x^2 + 6x.
  • Subtract (2x2+6x)(-2x^2 + 6x) from 2x22x-2x^2 - 2x, which results in 8x-8x.
  • Divide 8x-8x by xx, which gives 8-8.
  • Multiply 8-8 by x3x - 3, giving 8x+24-8x + 24.
  • Subtract (8x+24)(-8x + 24) from 8x+24-8x + 24, resulting in 0.

So, the quotient is x22x8x^2 - 2x - 8.

Factorization of x22x8x^2 - 2x - 8:

Now, we factor x22x8x^2 - 2x - 8. We need two numbers that multiply to give -8 and add to give -2. The numbers are 2 and -4.

Thus, x22x8x^2 - 2x - 8 factors as: (x4)(x+2)(x - 4)(x + 2)

Conclusion:

The complete factorization of the polynomial x35x22x+24x^3 - 5x^2 - 2x + 24 is: (x3)(x4)(x+2)(x - 3)(x - 4)(x + 2)

Hence, one of the factors is x+2x + 2, which corresponds to the second option.

Let me know if you need more details, and here are some related questions to expand on this:

  1. How do you perform synthetic division instead of long division?
  2. Can all cubic polynomials be factored using this method?
  3. How can you verify that x=3x = 3 is a root of the polynomial?
  4. What happens if a polynomial has no real roots?
  5. How can you use the Rational Root Theorem to find possible roots?

Tip: When factoring cubic polynomials, checking for simple roots like integers using synthetic division or the Rational Root Theorem can speed up the process.

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Math Problem Analysis

Mathematical Concepts

Algebra
Polynomial Division
Factoring Cubic Polynomials

Formulas

Polynomial division
Factoring quadratic equation ax^2 + bx + c

Theorems

Factor Theorem
Rational Root Theorem

Suitable Grade Level

Grades 9-12