1. If (x, y) is reflected in the x-axis, its image is the point (x, -y). The y-coordinate is negated when reflecting in the x-axis. The rule is (x, y) → (x, -y).
2. If (x, y) is reflected in the y-axis, its image is the point (-x, y). The x-coordinate is negated when reflecting in the y-axis. The rule is (x, y) → (-x, y).
3. If (x, y) is reflected in the line y = x, its image is (y, x). The line y = x is a line with a slope of 1 and a y-intercept of 0. The x-coordinate and the y-coordinate are switched when reflecting in the line y = x. The rule is (x, y) → (y, x).