Difficulty: Medium
Correct Answer: 256
Explanation:
Introduction / Context:This item tests correct interpretation of fractional exponents and order of operations. You must carefully compute a cube root and a square root, add the results, and then express the sum as the square root of an unknown number (?^(1/2)).
Given Data / Assumptions:
Concept / Approach:Evaluate the division 5568 ÷ 87 exactly, then take its cube root. Next, compute 72 × 2 and take the square root. Add the two results to obtain a value that must equal √?. Finally, square this sum to recover ?.
Step-by-Step Solution:
5568 ÷ 87 = 64 (since 87 × 64 = 5568).Cube root: 64^(1/3) = 4.Compute the second term: 72 × 2 = 144; √144 = 12.Sum of roots: 4 + 12 = 16.Since 16 = √?, we have ? = 16^2 = 256.Verification / Alternative check:Plug back: √256 = 16; left side is 4 + 12 = 16. Both sides match exactly.
Why Other Options Are Wrong:4 and 16 are intermediate root values, not ?. √2 is unrelated. 144 is the product 72 × 2 before taking the square root, not the required ?.
Common Pitfalls:Taking square root before multiplication, or misreading the cube root as a square root. Keep radical operations in the correct order.
Final Answer:256
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