What is the pre-image of vertex [tex]\( A' \)[/tex] if the rule that created the image is [tex]\( r_{y\text{-axis}} \)[/tex] given by [tex]\((x, y) \rightarrow (-x, y)\)[/tex]?

A. [tex]\( A(-4, 2) \)[/tex]

B. [tex]\( A(-2, -4) \)[/tex]

C. [tex]\( A(2, 4) \)[/tex]

D. [tex]\( A(4, -2) \)[/tex]



Answer :

To determine the pre-image of the given points under the transformation rule [tex]\( r_{y\text{-axis}}: (x, y) \rightarrow (-x, y) \)[/tex], we need to apply the reverse transformation to each point. The reverse transformation of [tex]\( (-x, y) \)[/tex] is [tex]\( (x, y) \)[/tex].

Let's find the pre-image of each point step by step:

1. For the point [tex]\( (-4, 2) \)[/tex]:

The transformation rule [tex]\( r_{y\text{-axis}} \)[/tex] sends [tex]\( (x, y) \)[/tex] to [tex]\( (-x, y) \)[/tex].

We perform the reverse transformation:
[tex]\[ (-x, y) = (-4, 2) \implies x = 4, y = 2 \][/tex]
Therefore, the pre-image of [tex]\( (-4, 2) \)[/tex] is [tex]\( (4, 2) \)[/tex].

2. For the point [tex]\( (-2, -4) \)[/tex]:

The reverse transformation:
[tex]\[ (-x, y) = (-2, -4) \implies x = 2, y = -4 \][/tex]
Thus, the pre-image of [tex]\( (-2, -4) \)[/tex] is [tex]\( (2, -4) \)[/tex].

3. For the point [tex]\( (2, 4) \)[/tex]:

The reverse transformation:
[tex]\[ (-x, y) = (2, 4) \implies x = -2, y = 4 \][/tex]
Hence, the pre-image of [tex]\( (2, 4) \)[/tex] is [tex]\( (-2, 4) \)[/tex].

To summarize, the pre-images of the given points are:
[tex]\[ A(-4, 2) \rightarrow (4, 2) \][/tex]
[tex]\[ A(-2, -4) \rightarrow (2, -4) \][/tex]
[tex]\[ A(2, 4) \rightarrow (-2, 4) \][/tex]