Difficulty: Easy
Correct Answer: ± 12
Explanation:
Introduction / Context:
The two-dimensional distance formula connects coordinate differences to the straight-line distance between points. Here, one point lies on the y-axis and the other on the x-axis, which simplifies computation because one coordinate in each point is zero.
Given Data / Assumptions:
Concept / Approach:
Use distance formula: For A(x1, y1) and B(x2, y2), distance d satisfies d^2 = (x2 − x1)^2 + (y2 − y1)^2. Substitute the known values, square the distance, and solve for x, remembering that squaring leads to two symmetric solutions (±) when isolating x.
Step-by-Step Solution:
Verification / Alternative check:
Check x = 12: distance^2 = 12^2 + 5^2 = 144 + 25 = 169 ⇒ distance = 13. Similarly for x = −12 because x^2 is the same; both satisfy the condition.
Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:
± 12
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