We want to know the coordinate of the point Y', which is part of the triangle X'Y'Z', and thus given by reflecting across the x-axis and then the y-axis. So, we will reflect the point Y across the x-axis and the y-axis.
The point Y is (3,2). Its reflection across the x-axis will be given by changing the sign of the y coordinate:
And the reflection of that point across the y-axis will be given by changing the sign of the x-coordinate:
This means that the coordinates of the point Y' are (-3,-2).