Pls explain why A (4,-2) change into A' (-4,2) why 4 Change to -4 and -2 change into 2

FIGURE

Dear student
                      As you can see Point A and Point A' are at equal distance.
                       
                     Now Point A is in fourth quadrant where x is positive and y negative as (4,-2)
                      but in case A' its in second quadrant where x is negative and y positive hence (-4,2)
                       so therefore 4 changes to -4 and -2 to 2.
Regards