Recall that when we reflect something across the x -axis, we are keeping x the same value and the y coordinate changes its sign. For example
So, if we have a point (a,b) the reflection across the x axis is (a,-b).
The point A is (2,2). So if we reflect it across the x axis, we keep the first coordinate the same and multiply the second one by -1. So we get A'(2,-1*2)=(2,-2).