Question

Would the rule be (x,y)->(-x,y) or (x,y)->(x,-y)?​

Answer 1

It would be (x,y)—>(x,-y)
Explanation
(-9,-(-1))=(-9,1)
(-9,-(-8))=(-9,8)
When there is two negatives like this
5-(-6) you will change signs meaning change -6 to 6

Answer 2

(x, y) -> (x, -y)

Explanation:

you can see the y values in the pre-image are multiplied by -1 to get the ones in the image, and the x values stay the same.