Which transformation is used for undoing the applied transformation:

To undo an applied transformation in computer graphics (or mathematics), apply its inverse transformation.

Key idea: the inverse transformation is the operation that exactly reverses the effect of the original transformation.

• Translation: a translation by (dx, dy) is undone by a translation by (−dx, −dy).

• Rotation: a rotation by θ is undone by a rotation by −θ (the inverse rotation).

• Scaling: scaling by a factor s is undone by scaling by 1/s (assuming s ≠ 0).

• Reflection: reflection across a line or plane is its own inverse (applying the same reflection again restores the original).

Note: terms like 'reverse transformation' or naming a specific transformation (for example, 'rotation transformation') do not by themselves specify the undo operation; the precise concept for undoing is the inverse transformation.