Reflect the point (3,−9)(3, -9)(3,−9) across the line y=−3y = -3y=−3.
(3,3)(3, 3)(3,3)
(3,−9)(3, -9)(3,−9)
(−3,−9)(-3, -9)(−3,−9)
(3,−15)(3, -15)(3,−15)