A line segment has endpoints at [tex]\((-1, 4)\)[/tex] and [tex]\((4, 1)\)[/tex]. Which reflection will produce an image with endpoints at [tex]\((-4, 1)\)[/tex] and [tex]\((-1, -4)\)[/tex]?

A. A reflection of the line segment across the [tex]\(x\)[/tex]-axis
B. A reflection of the line segment across the [tex]\(y\)[/tex]-axis
C. A reflection of the line segment across the line [tex]\(y = x\)[/tex]
D. A reflection of the line segment across the line [tex]\(y = -x\)[/tex]



Answer :

To determine which type of reflection produces the specified image of the line segment, we need to consider how different reflections transform the coordinates of the endpoints of the line segment.

Original Endpoints:
- Point A: [tex]\((-1, 4)\)[/tex]
- Point B: [tex]\( (4, 1) \)[/tex]

Target Endpoints after Reflection:
- Point A': [tex]\((-4, 1)\)[/tex]
- Point B': [tex]\((-1, -4)\)[/tex]

Let's evaluate each reflection option to see which produces the target endpoints:

1. Reflection across the [tex]\(x\)[/tex]-axis:
- Reflecting across the [tex]\(x\)[/tex]-axis changes the sign of the [tex]\(y\)[/tex]-coordinates.
- [tex]\((-1, 4) \to (-1, -4)\)[/tex]
- [tex]\((4, 1) \to (4, -1)\)[/tex]
- This does not match the target points [tex]\((-4, 1)\)[/tex] and [tex]\((-1, -4)\)[/tex].

2. Reflection across the [tex]\(y\)[/tex]-axis:
- Reflecting across the [tex]\(y\)[/tex]-axis changes the sign of the [tex]\(x\)[/tex]-coordinates.
- [tex]\((-1, 4) \to (1, 4)\)[/tex]
- [tex]\((4, 1) \to (-4, 1)\)[/tex]
- This does not match the target points [tex]\((-4, 1)\)[/tex] and [tex]\((-1, -4)\)[/tex].

3. Reflection across the line [tex]\(y=x\)[/tex]:
- Reflecting across the line [tex]\(y=x\)[/tex] swaps the [tex]\(x\)[/tex] and [tex]\(y\)[/tex] coordinates.
- [tex]\((-1, 4) \to (4, -1)\)[/tex]
- [tex]\((4, 1) \to (1, 4)\)[/tex]
- This does not match the target points [tex]\((-4, 1)\)[/tex] and [tex]\((-1, -4)\)[/tex].

4. Reflection across the line [tex]\(y=-x\)[/tex]:
- Reflecting across the line [tex]\(y=-x\)[/tex] swaps and negates the [tex]\(x\)[/tex] and [tex]\(y\)[/tex] coordinates.
- [tex]\((-1, 4) \to (-4, -1)\)[/tex]
- [tex]\((4, 1) \to (-1, -4)\)[/tex]

Let's match the reflected coordinates with the target coordinates:
- From [tex]\((-1, 4)\)[/tex], we get the reflected point [tex]\((-4, -1)\)[/tex]. This does not match perfectly. Therefore, we need to re-evaluate the actual transformation for Point B',' which should go as:

[tex]\((-1, 4)\)[/tex] becomes [tex]\((-4, 1)\)[/tex] and [tex]\((4, 1)\)[/tex] becomes [tex]\((-1, -4)\)[/tex].

Thus, reflecting across the line [tex]\(y=-x\)[/tex] gives:
- Original point [tex]\((-1, 4)\)[/tex] reflects to [tex]\((-4, 1)\)[/tex], which matches one of the target coordinates.
- Original point [tex]\((4, 1)\)[/tex] reflects to [tex]\((-1, -4)\)[/tex], which matches the other target coordinate.

Reflection across the line [tex]\(y=-x\)[/tex] correctly produces the target endpoints.

Therefore, the correct reflection is:
A reflection of the line segment across the line [tex]\(y=-x\)[/tex].

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