From the figure, we have the following coordinates of the vertices :
a. Rotation of 180 degrees about the origin has a rule of :
The sign of the coordinates will change from positive to negative or negative to positive.
The new coordinates will be :
The graph will be :
b. Reflection across the x-axis has a rule of :
Only the y coordinate will change its sign.
So from the coordinates we got in a.
The graph will be :