Match a transformed sum to a scaled reference expression (clarified brackets): Evaluate A = {[(3^(−2))^(−5)]^(1/5)} + {[(4^(−3))^(−6)]^(1/6)} − 1 and express A as K × {[(2^(−3))^(−4)]^(1/4)}. Find K.
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A9
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B8
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C27
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D1/3
Answer
Correct Answer: 9
Explanation
Introduction / Context:This item uses nested exponents with negative and fractional powers. By simplifying each bracket carefully, the left-hand side turns into a simple integer. The right-hand side is a separate expression; the task is to express the left as a constant multiple K of the right and identify K.Given Data / Assumptions:
- A = {[(3^(−2))^(−5)]^(1/5)} + {[(4^(−3))^(−6)]^(1/6)} − 1.
- Reference R = {[(2^(−3))^(−4)]^(1/4)}.
Concept / Approach:Use (a^m)^n = a^(mn) and a^(−k) = 1/a^k. Work inside-out, simplify each bracket to a simple power of the base, then add and compare to R to extract K = A / R.Step-by-Step Solution:
[(3^(−2))^(−5)]^(1/5) = 3^( (−2)*(−5)*(1/5) ) = 3^2 = 9.[(4^(−3))^(−6)]^(1/6) = 4^( (−3)*(−6)*(1/6) ) = 4^3 = 64.A = 9 + 64 − 1 = 72.R = {[(2^(−3))^(−4)]^(1/4)} = 2^( (−3)*(−4)*(1/4) ) = 2^3 = 8.Thus A = 72 = 9 × 8 = 9 × R ⇒ K = 9.Verification / Alternative check:Compute numerically: A = 72, R = 8, ratio 72/8 = 9. Everything matches exactly.
Why Other Options Are Wrong:
- 8: That is R, not the multiplier.
- 27, 1/3: Incorrect constants that would not satisfy A = K × R.
Common Pitfalls:Dropping outer exponents or forgetting to multiply exponents in the correct order; also, misapplying negative exponent rules.
Final Answer:
9