How do you reflect a shape across line x1?

To reflect a shape across a vertical line, such as line ( x = x_1 ), you first determine the horizontal distance from each point of the shape to the line. For a point ( (x, y) ), the reflected point will have coordinates ( (2x_1 - x, y) ). This process is repeated for all points of the shape to obtain the reflected image. The resulting shape will be a mirror image of the original across the specified line.