Simplify $\left(\dfrac{2}{x}\right)^{3}$ for $x \ne 0$.
A$\dfrac{8}{x^{3}}$
B$\dfrac{2}{x^{3}}$
C$\dfrac{8}{3x}$
D$\dfrac{6}{x^{3}}$
Answer & Solution
Correct answer: A. $\dfrac{8}{x^{3}}$
Apply $\left(\dfrac{a}{b}\right)^{n} = \dfrac{a^{n}}{b^{n}}$:
$\left(\dfrac{2}{x}\right)^{3} = \dfrac{2^{3}}{x^{3}} = \dfrac{8}{x^{3}}$.
- Trap B ($6 = 2 \cdot 3$) treats $2^3$ as $2 \cdot 3$.
- Trap C only cubes the denominator.
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