Which rule describes a transformation across the y-axis?

 The required transformation rule is given by

(x, y)  >  (-x, y).

Step-by-step explanation:  We are given to write a rule that describes a transformation across the y-axis.

We know that

if a point is reflected across the y-axis, then the sign before the x co-ordinate changes.

That is, if the point (x, y) is reflected (transformed) across the y-axis, then its new co-ordinates will be

(-x, y).

Thus, the required transformation rule is given by

(x, y)  >  (-x, y).

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im not sure

i have not got your picture clearly so see it once again