Explanation:
We have the point (-8, 7)
When we reflect across the X-AXIS, then the Y coordinate changes signs
When we reflect across the Y-AXIS, then the X coordinate changes signs
So when we reflect (-8, 7) across the x-axis, it becomes (-8, -7) since we change signs for the Y coordinate from +7 to -7
Reflecting across the Y, it becomes (8, 7), because we change signs from -8 to +8