Math Problem Statement

x-5 divided by x^3- 2x^2-11x-20

Solution

To simplify the expression x5x32x211x20\frac{x - 5}{x^3 - 2x^2 - 11x - 20}, we can start by factoring the cubic polynomial in the denominator, if possible.

Step 1: Factor the denominator

We are looking to factor: x32x211x20x^3 - 2x^2 - 11x - 20 Using the Rational Root Theorem, we test possible rational roots such as ±1,±2,±4,±5,±10,±20\pm 1, \pm 2, \pm 4, \pm 5, \pm 10, \pm 20.

Let's start by checking x=4x = -4:

(4)32(4)211(4)20=6432+4420=72(-4)^3 - 2(-4)^2 - 11(-4) - 20 = -64 - 32 + 44 - 20 = -72 This is not zero, so x=4x = -4 is not a root.

Now, let's check x=2x = -2:

(2)32(2)211(2)20=88+2220=14(-2)^3 - 2(-2)^2 - 11(-2) - 20 = -8 - 8 + 22 - 20 = -14 So x=2x = -2 is not a root.

We will divide the polynomial

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Math Problem Analysis

Mathematical Concepts

Algebra
Polynomial Division
Factoring Cubic Polynomials

Formulas

Rational Root Theorem: f(x) = a_nx^n + a_{n-1}x^{n-1} + ... + a_0, possible roots are divisors of a_0
Polynomial division

Theorems

Rational Root Theorem
Factorization of Polynomials

Suitable Grade Level

Grades 10-12