A dilation with scale factor k=−2k=-2k=−2 centered at origin maps (3,4)(3, 4)(3,4) to:
(6,8)(6, 8)(6,8)
(−6,−8)(-6, -8)(−6,−8)
(−1.5,−2)(-1.5, -2)(−1.5,−2)
(1,2)(1, 2)(1,2)