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Ch. R - Review of Basic Concepts
Lial - College Algebra 13th Edition
Lial13th EditionCollege AlgebraISBN: 9780136881063Not the one you use?Change textbook
Chapter 1, Problem 73

Factor each polynomial. See Examples 5 and 6. 8-a3

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Recognize that the expression \$8 - a^3\( is a difference of cubes because \(8\) can be written as \)2^3\( and \)a^3$ is already a cube.
Recall the formula for factoring a difference of cubes: \(x^3 - y^3 = (x - y)(x^2 + xy + y^2)\).
Identify \(x = 2\) and \(y = a\) in the expression \$8 - a^3$.
Apply the difference of cubes formula: write \((2 - a)(2^2 + 2 \cdot a + a^2)\).
Simplify the terms inside the second parenthesis to get \((2 - a)(4 + 2a + a^2)\).

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Key Concepts

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

Difference of Cubes

The difference of cubes formula states that a³ - b³ = (a - b)(a² + ab + b²). It is used to factor expressions where one term is a cube subtracted from another. Recognizing this pattern helps in breaking down polynomials like 8 - a³, since 8 is 2³.
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Identifying Perfect Cubes

A perfect cube is a number or expression raised to the third power, such as 8 (2³) or a³. Identifying perfect cubes in a polynomial is essential before applying the difference of cubes formula. This step ensures the correct factorization approach.
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Polynomial Factoring Techniques

Factoring polynomials involves rewriting them as products of simpler polynomials. Techniques include factoring out common terms, grouping, and special formulas like difference of squares or cubes. Mastery of these methods is crucial for simplifying expressions and solving equations.
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Introduction to Factoring Polynomials