Chapter 0: Problem 66
Factor the expression completely. $$ 27 a^{3}+b^{6} $$
Short Answer
Expert verified
The complete factorization is \((3a + b^2)(9a^2 - 3ab^2 + b^4)\).
Step by step solution
01
Recognize the Sum of Cubes
The expression \( 27a^3 + b^6 \) can be recognized as a sum of cubes because \( 27a^3 = (3a)^3 \) and \( b^6 = (b^2)^3 \). This gives us the structure \( (3a)^3 + (b^2)^3 \).
02
Apply the Sum of Cubes Formula
The sum of cubes formula is \( x^3 + y^3 = (x+y)(x^2 - xy + y^2) \). Here, \( x = 3a \) and \( y = b^2 \). Substitute these into the formula: \((3a + b^2)((3a)^2 - (3a)(b^2) + (b^2)^2)\).
03
Simplify the Polynomial
Now, simplify the expression inside the parentheses:1. \((3a)^2 = 9a^2\)2. \(-(3a)(b^2) = -3ab^2\)3. \((b^2)^2 = b^4\)Substituting back, we get:\((3a + b^2)(9a^2 - 3ab^2 + b^4)\).
04
Verify the Factorization
Double-check by expanding \((3a + b^2)(9a^2 - 3ab^2 + b^4)\) to ensure it simplifies back to \(27a^3 + b^6\). By distribution, the terms will expand and combine back to the original expression, confirming the factorization is correct.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Sum of Cubes
The sum of cubes is a concept in algebra where two cubed terms are added together. Recognizing these sums allows us to simplify expressions by factoring them in a specific way. In our exercise, the components involved are \( 27a^3 \) and \( b^6 \), which can be rewritten as \( (3a)^3 \) and \( (b^2)^3 \) respectively. This aligns with the structure of the sum of cubes formula: \( x^3 + y^3 = (x+y)(x^2 - xy + y^2) \).
Applying this formula involves:
Applying this formula involves:
- Identifying \( x \) and \( y \) as bases of the cubed terms.
- Rewriting each term to show visibly it's a cube, such as \( (3a)^3 + (b^2)^3 \).
- Using the formula to break it into a factorable form.
Polynomial Algebra
Polynomial algebra is the area of mathematics that involves manipulating expressions with variables raised to whole-number exponents and combining them through operations like addition, subtraction, and multiplication.
In our current exercise, polynomial algebra is used to compose and simplify expressions like \( 27a^3 + b^6 \).
In our current exercise, polynomial algebra is used to compose and simplify expressions like \( 27a^3 + b^6 \).
- Polynomials can include terms with variables, constants, and exponents.
- The expression in our example is a binomial—a polynomial with two terms, each a cube, which can be simplified using our factorization strategies.
Algebra Factorization
Algebra factorization is the process of breaking down a complex expression into simpler "factors" that multiply together to give back the original expression.In our exercise, we take the sum of cubes - \( 27a^3 + b^6 \) - and apply the sum of cubes formula to factor it. Factoring involves recognizing patterns and applying formulas to make a complex equation simpler.
Here's a breakdown:
Here's a breakdown:
- Identify the structure or special form of the polynomial, like the sum of cubes.
- Apply known algebraic identities or formulas, here it was \( x^3 + y^3 = (x+y)(x^2 - xy + y^2) \).
- Simplify the resultant factors, ensuring they multiply back to the original expression to verify correctness.