Chapter 5: Problem 85
Perform the indicated operations. $$ (a+b)(a-b)(a-3 b) $$
Short Answer
Expert verified
The expression simplifies to \(a^3 - 3a^2b - ab^2 + 3b^3\).
Step by step solution
01
Apply the Difference of Squares Formula
The expression \((a+b)(a-b)\) is a difference of squares. Applying the formula, it simplifies to: \((a+b)(a-b) = a^2 - b^2\). Rewrite the expression as \((a^2 - b^2)(a-3b)\).
02
Distribute the First Term
Distribute \(a^2\) from \((a^2 - b^2)(a-3b)\). Multiply \(a^2\) by \(a\) and \(-3b\) separately: \(a^2(a) = a^3\), and \(a^2(-3b) = -3a^2b\).
03
Distribute the Second Term
Now distribute \(-b^2\) from \((a^2 - b^2)(a-3b)\). Multiply \(-b^2\) by \(a\) and \(-3b\) separately: \(-b^2(a) = -ab^2\), and \(-b^2(-3b) = 3b^3\).
04
Combine Like Terms
Combine all the terms obtained from distribution: \(a^3 - 3a^2b - ab^2 + 3b^3\). Check for like terms, but there are none, so this is the final simplified expression.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Difference of Squares
The difference of squares is a powerful algebraic concept that simplifies certain types of expressions. When you encounter an expression like
**Understanding the Formula**
The formula for the difference of squares states:
Instead of distributing each term individually from one binomial to the other, recognizing a difference of squares allows you to jump immediately to a cleaner, simplified expression. In our original problem, applying the difference of squares simplifies the expression
- \((a+b)(a-b)\),
**Understanding the Formula**
The formula for the difference of squares states:
- \((a-b)(a+b) = a^2 - b^2\).
Instead of distributing each term individually from one binomial to the other, recognizing a difference of squares allows you to jump immediately to a cleaner, simplified expression. In our original problem, applying the difference of squares simplifies the expression
- from \((a+b)(a-b)(a-3b)\) to \((a^2 - b^2)(a-3b)\),
Distributive Property
The distributive property is a fundamental algebraic principle that lets you simplify and solve equations by handling multiplication across a sum or difference. When distributing, each term inside a parenthesis is multiplied by a term outside the parenthesis.
**Applying the Distributive Property**
To apply this concept, imagine you have an expression like:
Distribute the terms sequentially:
**Applying the Distributive Property**
To apply this concept, imagine you have an expression like:
- \((a^2 - b^2)(a-3b)\),
Distribute the terms sequentially:
- First, distribute \(a^2\) to both terms within the \((a-3b)\) binomial, giving you \(a^2 \times a = a^3\) and \(a^2 \times -3b = -3a^2b\).
- Next, distribute \(-b^2\) similarly, leading to \(-b^2 \times a = -ab^2\) and \(-b^2 \times -3b = 3b^3\).
Combining Like Terms
Combining like terms is an essential strategy in algebra used to simplify expressions and solve equations.
**Identifying Like Terms**
Like terms are terms that have the same variable raised to the same power. In the expression
**Combining Process**
In this example, you notice that each term is distinct in terms of its variable components and powers:
Combining like terms often results in fewer terms, making complex expressions more manageable and clear to understand or further process in equations.
**Identifying Like Terms**
Like terms are terms that have the same variable raised to the same power. In the expression
- \(a^3 - 3a^2b - ab^2 + 3b^3\),
**Combining Process**
In this example, you notice that each term is distinct in terms of its variable components and powers:
- \(a^3\) is not similar to any other terms;
- \(-3a^2b\), \(-ab^2\), and \(3b^3\) are also unique.
Combining like terms often results in fewer terms, making complex expressions more manageable and clear to understand or further process in equations.