we have that
First
Rotate 180 degrees clockwise about the origin
the rule is
S(x,y) --------> S'(-x,-y)
Second
translated 6 units to the left
the rule is
S'(-x,-y) -----> S''(-x-6,-y)
Third
Reflect across the line y=x
the rule is
the x-coordinate and y-coordinate change places
S''(-x-6,-y) ------> S''''(-y,-x-6)
therefore
the final answer is (-y,-x-6)