A reflection across an X axis, does not change the Y value.
So we will just look at the X value.
The original K point is on X = -4.
To reflect across X = -2, find the distance from K to the line , - 4 to - 2 is 2 units to the right. This means the reflected point would need to be 2 units to the right of the line.
2 units to the right of - 2 would be 0 ( -2 + 2 = 0)
Now that point also gets reflected across a line at x = 2.
Like the first one, find the distance from the point to the line, 0 to 2 is 2 units, so now the new point needs to be 2 units to the right of the line.
2 + 2 = 4.
K' would be located at (4,-2)