Difficulty: Medium
Correct Answer: 5364
Explanation:
Introduction / Context:
This problem tests use of a cube identity:
a^3 + b^3 + c^3 - 3abc = (a + b + c)(a^2 + b^2 + c^2 - ab - bc - ca).
The given expression is exactly 2 times that identity form. Using the identity avoids heavy cube calculations.
Given Data / Assumptions:
Concept / Approach:
Factor out 2, then use the identity for a^3 + b^3 + c^3 - 3abc. Because a, b, c are consecutive integers, the symmetric difference term (a^2 + b^2 + c^2 - ab - bc - ca) becomes small, making the product manageable.
Step-by-Step Solution:
Verification / Alternative check:
Because the numbers are close, the difference-based formula for S is very reliable and quick. If you compute directly with cubes, you get the same 5364 but with much heavier arithmetic.
Why Other Options Are Wrong:
Common Pitfalls:
Using the identity but forgetting to multiply by 2 at the end, or computing S as (a-b)^2 + (b-c)^2 + (c-a)^2 without halving.
Final Answer:
5364
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