The y-axis<span> is the point (-x,</span>y<span>). </span>Reflect over the y<span> = x: When you </span>reflect<span> a point </span>across<span> the line </span>y<span> = x, the x-coordinate and </span>y<span>-coordinate change places. If you </span>reflect over<span> the line </span>y<span> = -x, the x-coordinate and </span>y<span>-coordinate change places and are negated (the signs are changed)</span>