Which term refers to creating a mirror image of a figure on the opposite side of a line?

The term that refers to creating a mirror image of a figure on the opposite side of a line is "flip transformation." This type of transformation is also known as reflection. When a shape is reflected across a line, each point of the original figure is mapped to a point on the opposite side of the line, at an equal distance from the line. This results in a figure that is a mirror image of the original.

The other transformation types serve different purposes: a slide transformation involves moving a shape without changing its orientation; a rotate transformation involves turning the shape around a fixed point; and a scale transformation changes the size of a shape while maintaining its proportions. Each of these transformations has distinct characteristics that do not involve creating a mirror image across a line.