Explanation:
So if you are reflecting across the x-axis then the point after the reflection should be (x,-y). If you are reflecting across the y-axis the the point after the reflection should be (-x,y). If you are reflecting across the line y=x, then the point after the reflection should be (y,x) If you are reflecting across the line y=-x, then the point after the reflection should be (-y, -x). If you are reflecting across the origin, then the point after the reflection should be(-x,-y). Hope this helps.