Explanation:
the other answer had the right thought, but they mixed up something about positive and negative.
as x increases from left to right, and y from the bottom up, moving to the right means increasing x.
to use the same example : point Z
the x coordinate of Z is 1.
the x coordinate of Z' is 3.
the y coordinate of Z is 5.
the y coordinate of Z' is 4.
so, what happened ?
x increases by 2, y decreases by 1.
(x, y) -> (x+2, y-1)