Chapter 0: Problem 13
Simplify the expression. $$ \frac{a^{3}+b^{3}}{a+b} $$
Short Answer
Expert verified
The simplified expression is \(a^2 - ab + b^2\).
Step by step solution
01
Recognize the Formula
Recognize that the expression \(a^3 + b^3\) can be simplified using the formula for the sum of cubes, which is \(a^3 + b^3 = (a + b)(a^2 - ab + b^2)\).
02
Substitute the Formula
Substitute \(a^3 + b^3\) with \((a + b)(a^2 - ab + b^2)\) in the given expression to get:\(\frac{(a + b)(a^2 - ab + b^2)}{a + b}\)
03
Simplify by Canceling
Since \(a + b\) is present in both the numerator and the denominator, you can cancel them out.The expression simplifies to:\(a^2 - ab + b^2\)
04
Write the Final Expression
The simplified expression is \(a^2 - ab + b^2\). This is the answer after simplifying the given expression using the formula for the sum of cubes.
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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 special algebraic expression that takes the form \( a^3 + b^3 \). It is important to recognize this form because it can be factored using a specific formula. Understanding this can greatly simplify your work, just like it does for the original exercise.To factor the sum of cubes, use the formula: \[a^3 + b^3 = (a + b)(a^2 - ab + b^2)\]Here's a breakdown of what each component represents:
- \( (a + b)\) is a simple sum of the bases \(a\) and \(b\).
- \( (a^2 - ab + b^2)\) is a trinomial that comprises the squares and the product of these bases.
Factoring Polynomials
Factoring polynomials is a fundamental skill in algebra. It's used to break down complex expressions into simpler parts. In our exercise, factoring is the key technique used to dismantle \( a^3 + b^3 \).We employ the sum of cubes formula from the previous section. It helps to express \( a^3 + b^3 \) in terms of \( (a + b)\) and \( (a^2 - ab + b^2)\). This process involves writing a polynomial as a product of its simpler factors. If you have these factors, it often becomes easier to solve or simplify algebraic expressions.For example:
- Recognize polynomial forms like sum of cubes, difference of cubes, or quadratic trinomials.
- Apply the corresponding formulas to factor them systematically.
Simplification Techniques
Simplification is about reducing expressions into their most basic form. It's a crucial skill in algebra, as it makes problems easier to tackle. In our problem, simplification involves a few different strategies.First, we use the sum of cubes formula, identifying the expression correctly and substituting it with its factored equivalent: \( \frac{(a + b)(a^2 - ab + b^2)}{a + b} \)Next, we simplify by canceling out terms that appear in both the numerator and the denominator. In our case, \(a + b\) is present in both, allowing us to remove it:
- Cancel common factors when both numerator and denominator share them.