Difficulty: Easy
Correct Answer: 1/x^2
Explanation:
Introduction / Context:This problem combines cube roots with integer and negative exponents. Converting all radicals to fractional exponents allows straightforward combination via exponent addition and subtraction rules.Given Data / Assumptions:
Concept / Approach:Use ∛(x^k) = x^(k/3). Then combine exponents linearly: when multiplying, add exponents; when dividing, subtract exponents. Keep track of the signs carefully, especially for the negative power term x^(−3).Step-by-Step Solution:
∛(x^6) = x^(6/3) = x^2.∛(x^12) = x^(12/3) = x^4.∛(x^9) = x^(9/3) = x^3.Combine: x^2 / x^4 × x^(−3) × x^3 = x^(2 − 4 − 3 + 3) = x^(−2) = 1/x^2.Verification / Alternative check:Pick x = 2: ∛(64)/∛(4096) × 2^(−3) × ∛(512) = 4/16 × 1/8 × 8 = (1/4) × (1/8) × 8 = 1/4 = 1/2^2, confirming 1/x^2.
Why Other Options Are Wrong:
Common Pitfalls:Forgetting that dividing by x^4 reduces exponent by 4, or cancelling x^(−3) incorrectly with x^3.
Final Answer:
1/x^2
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