Difficulty: Easy
Correct Answer: (-3, -6)
Explanation:
Introduction / Context:
This problem checks your understanding of reflections in coordinate geometry, specifically reflection in the x axis. Such transformations are fundamental when working with graphs, symmetry, and geometric interpretations on the Cartesian plane.
Given Data / Assumptions:
Concept / Approach:
Key ideas:
Step-by-Step Solution:
Start with the original point P(−3, 6).
Under reflection in the x axis, x remains the same, so x = −3.
The y coordinate changes sign: y becomes −6.
Therefore the image point P′ is (−3, −6).
Verification / Alternative check:
You can visualise the point on the coordinate plane. P(−3, 6) lies in the second quadrant. Reflecting in the x axis moves it straight down vertically to the point with the same x coordinate and the opposite y coordinate, which is (−3, −6) in the third quadrant. The vertical distance from the x axis is 6 units in both cases, confirming the reflection.
Why Other Options Are Wrong:
Option a: (3, 6) represents reflection in the y axis, not in the x axis.
Option b: (6, −3) changes both coordinates and does not preserve the correct symmetric distance.
Option d: (−6, 3) is reflection about the line y = x combined with sign changes and is not appropriate here.
Option e: (3, −6) corresponds to reflection in the origin, changing both signs, rather than only flipping across the x axis.
Common Pitfalls:
A common mistake is to change the wrong coordinate or both coordinates. Always remember: reflection in the x axis affects only the y coordinate, and reflection in the y axis affects only the x coordinate. Keeping a mental picture of the coordinate plane helps avoid confusion.
Final Answer:
The image of the point after reflection in the x axis is (−3, −6).
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