Hello!
First of all, we need to reflect our point across the line y=3. This is a horizontal line. Therefore, our y-value will change. If we reflect, we get the point (0,3).
Now we reflect across the x-axis, which is also a vertical line. When reflecting across an axis, you just switch to the inverse of a number. This gives us (0,-3).
Therefore, our answer is (0, -3).
I hope this helps!