Chapter 5: Problem 62
Factor $$ \left(x^{2 a}-1\right)^{3}-x^{6 a} $$
Short Answer
Expert verified
-1 (3x^{4a} - 3x^{2a} + 1)
Step by step solution
01
Understand the problem
We need to factor the expression \(\left(x^{2a} - 1 \right)^{3} - x^{6a}\). Notice that both terms can be related to a difference of cubes.
02
Rewrite the expression
Rewrite the expression realizing that \(x^{6a} = (x^{2a})^3\). Therefore, the expression becomes: \(\left(x^{2a} - 1 \right)^3 - \left(x^{2a} \right)^3\).
03
Recognize the difference of cubes
Now that the expression is in the form of a difference of cubes \(a^3 - b^3\), where \(a = x^{2a} - 1\) and \(b = x^{2a}\), we can use the formula for factoring a difference of cubes: \(a^3 - b^3 = (a - b)(a^2 + ab + b^2)\).
04
Apply the difference of cubes formula
Apply the difference of cubes formula: \(\left(x^{2a} - 1\right)^3 - \left(x^{2a}\right)^3 = \left( \left(x^{2a} - 1\right) - x^{2a} \right) \left( \left(x^{2a} - 1 \right)^2 + \left(x^{2a} - 1\right)x^{2a} + (x^{2a})^2 \right)\).
05
Simplify the expression
Simplify the terms inside the factored form: \(\left(\left(x^{2a} - 1\right) - x^{2a}\right) = -1\) and \(\left(\left(x^{2a} - 1 \right)^2 + \left(x^{2a} - 1\right)x^{2a} + (x^{2a})^2\right) = \left(x^{4a} - 2x^{2a} + 1 + x^{4a} - x^{2a} + x^{4a} \right) = 3x^{4a} - 3x^{2a} + 1\).
06
Combine the simplified parts
Combining the simplified terms, the factored form of the expression \(\left(x^{2a} - 1 \right)^{3} - x^{6a}\) is \( -1 \left(3x^{4a} - 3x^{2a} + 1 \right)\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
difference of cubes
The difference of cubes is a critical concept in algebra. When you have two terms that are both perfect cubes subtracted from one another, the resulting expression can be factored in a specific way. The general formula for factoring the difference of cubes is \[a^3 - b^3 = (a - b)(a^2 + ab + b^2)\]. This formula helps break down complex polynomial expressions.
In our exercise, we rewrote the expression \[\left(x^{2a} - 1\right)^3 - x^{6a}\]as \[\left(x^{2a} - 1\right)^3 - \left(x^{2a}\right)^3\].
This enabled us to recognize the structure as a difference of cubes, where \[a = x^{2a} - 1\]and \[b = x^{2a}\].
By identifying these parts, we utilized the difference of cubes formula to further factor the expression.
In our exercise, we rewrote the expression \[\left(x^{2a} - 1\right)^3 - x^{6a}\]as \[\left(x^{2a} - 1\right)^3 - \left(x^{2a}\right)^3\].
This enabled us to recognize the structure as a difference of cubes, where \[a = x^{2a} - 1\]and \[b = x^{2a}\].
By identifying these parts, we utilized the difference of cubes formula to further factor the expression.
simplifying expressions
Simplifying expressions is a vital skill in algebra that allows you to rewrite expressions in a more manageable or insightful form. In our exercise, after applying the difference of cubes formula, we simplified the expression by addressing each term individually.
First, we had \[\left(\left(x^{2a} - 1\right) - x^{2a}\right)\]. After simplifying, it became \[-1\].
Next, we simplified the larger polynomial inside the parentheses:
By breaking the expression into smaller parts, the simplification process became more manageable.
First, we had \[\left(\left(x^{2a} - 1\right) - x^{2a}\right)\]. After simplifying, it became \[-1\].
Next, we simplified the larger polynomial inside the parentheses:
- \[\left(x^{2a} - 1\right)^2\]
- \[\left(x^{2a} - 1\right)x^{2a}\]
- \[(x^{2a})^2\]
By breaking the expression into smaller parts, the simplification process became more manageable.
factoring techniques
Factoring techniques are various strategies used to rewrite an expression as a product of its factors. These techniques are essential for solving polynomial equations, among other applications. In our exercise, we primarily used the technique of factoring a difference of cubes.
However, there are several other factoring techniques, such as:
In particular, recognizing special patterns like the difference of cubes can simplify what initially appears to be a daunting problem. Always look for these patterns before proceeding with more complex factoring steps.
However, there are several other factoring techniques, such as:
- Factoring out the greatest common factor (GCF)
- Factoring by grouping
- Factoring trinomials
- Using special products (like difference of squares)
In particular, recognizing special patterns like the difference of cubes can simplify what initially appears to be a daunting problem. Always look for these patterns before proceeding with more complex factoring steps.