Answer:
Translations mapping = (x, y) -----> (x+a, y+b)
Reflections across the y-axis = (x, y) -----> (-x, y)
Reflections across the x-axis = (x, y) -----> (x, -y)
Rotation: 90 degree: (x, y)-----> ( -y, x )
Rotation: 180 degree: (x, y)-----> (-x, -y)
Rotation: 270 degree: (x, y)-----> (y, -x)