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Ch. P - Fundamental Concepts of Algebra
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Not the one you use?Change textbook
Chapter 1, Problem 66

Factor completely, or state that the polynomial is prime. 5x345x5x^3−45x

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1
Identify the greatest common factor (GCF) of the terms in the polynomial \$5x^3 - 45x$. The GCF is the largest expression that divides both terms evenly.
Factor out the GCF from each term. Since the GCF is \$5x$, rewrite the polynomial as \(5x(\ldots)\).
Divide each term by the GCF to find the remaining factor inside the parentheses: \(5x^3 \div 5x = x^2\) and \(-45x \div 5x = -9\).
Write the factored form as \$5x(x^2 - 9)$.
Recognize that \(x^2 - 9\) is a difference of squares, which can be factored further using the formula \(a^2 - b^2 = (a - b)(a + b)\). Here, \(a = x\) and \(b = 3\), so factor it as \((x - 3)(x + 3)\).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Factoring Polynomials

Factoring polynomials involves rewriting a polynomial as a product of simpler polynomials or factors. This process helps simplify expressions and solve polynomial equations. Common methods include factoring out the greatest common factor, grouping, and special products.
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Greatest Common Factor (GCF)

The greatest common factor is the largest expression that divides all terms of a polynomial without leaving a remainder. Factoring out the GCF is often the first step in factoring polynomials, simplifying the expression and making further factoring easier.
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Prime Polynomials

A prime polynomial is one that cannot be factored further over the set of real numbers. After attempting all factoring methods, if no factors other than 1 and the polynomial itself are found, the polynomial is considered prime.
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