Questions: Select the correct answer.
What is the factored form of 343+x^6 ?
A. (7-x)(49+7x+x^2)
B. (7+x)(49-7x+x^2)
C. (7-x^2)(49+7x^2+x^4)
D. (7+x^2)(49-7x^2+x^4)
Transcript text: Select the correct answer.
What is the factored form of $343+x^{6} ?$
A. $(7-x)\left(49+7 x+x^{2}\right)$
B. $(7+x)\left(49-7 x+x^{2}\right)$
C. $\left(7-x^{2}\right)\left(49+7 x^{2}+x^{4}\right)$
D. $\left(7+x^{2}\right)\left(49-7 x^{2}+x^{4}\right)$
Solution
Solution Steps
To factor the expression \(343 + x^6\), we recognize that \(343\) is a perfect cube, specifically \(7^3\). The expression can be rewritten as a sum of cubes: \(7^3 + (x^2)^3\). We can use the sum of cubes formula, which is \(a^3 + b^3 = (a + b)(a^2 - ab + b^2)\), where \(a = 7\) and \(b = x^2\).
Solution Approach
Recognize the expression as a sum of cubes.
Apply the sum of cubes formula.
Step 1: Recognizing the Expression
The expression \(343 + x^6\) can be rewritten as \(x^6 + 343\). Noticing that \(343\) is a perfect cube, we can express it as \(7^3\). Thus, we have:
\[
x^6 + 343 = x^6 + 7^3
\]
Step 2: Applying the Sum of Cubes Formula
We can apply the sum of cubes formula, which states:
\[
a^3 + b^3 = (a + b)(a^2 - ab + b^2)
\]
In our case, let \(a = x^2\) and \(b = 7\). Therefore, we can factor the expression as follows: