Swapping & Negating: Error Analysis & Misconceptions

Mathematics
Year 9
12 questions
~24 mins
1 views0 downloads

About This Worksheet

A worksheet focusing on common errors and misconceptions related to swapping and negating coordinates during reflection across the line y = -x. Designed to develop understanding through error analysis and problem solving.

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Full preview • 12 questions

Swapping & Negating: Error Analysis & Misconceptions

Subject: MathematicsGrade: Year 9
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Untitled Worksheet

Grade Year 9
A

Practice Questions

Answer all questions. Show your working in the grid spaces provided.
1.
Reflect the point (3, -5) across the line y = -x. State the new coordinates.
[2 marks]
2.
A student incorrectly reflects the point (-2, 4) as (4, -2) when reflecting across y = -x. Identify and explain the mistake made.
[3 marks]
3.
Given the point (x, y), write the general formula for its reflection across y = -x.
[2 marks]
4.
Plot and reflect the point (1, -2) across y = -x on the grid. Write the reflected coordinates.
[2 marks]
5.
A reflection of (5, -3) should produce which coordinates? Confirm if swapping and negating are done correctly.
[2 marks]
6.
Explain why simply swapping the coordinates without negating does not produce the correct reflection across y = -x.
[3 marks]
7.
A point (x, y) is reflected across y = -x resulting in (-y, -x). If the reflected point is (4, -3), what was the original point?
[2 marks]
8.
Identify the common misconception students have when reflecting points across y=-x and suggest a correct approach.
[3 marks]
9.
Construct a triangle with vertices (2, -1), (-3, 4), and (0, 0). Reflect it across y = -x. What are the new vertices?
[3 marks]
10.
A student claims that reflecting a point across y = -x always results in a point with both coordinates negative. Is this true? Explain.
[3 marks]
11.
Calculate the reflection of the point (-6, 2). Show your working.
[2 marks]
12.
Identify and correct the mistake in this student’s reflection: they reflected (4, -5) as (5, -4).
[3 marks]

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Details

Created
1/1/2026
Updated
1/1/2026
Type
worksheet