Triangle DJM has vertices D(-1, 2), J(-3, 4), and M(1, 4). What are the coordinates of the image of triangle DJM after a dilation by a scale factor of 2 and then a rotation 90° counterclockwise??

Let x have probability generating function gx (s) and let un generating function u(s) of the sequence uo, u1, satisfies p(x > n). show that the (1- s)u(s) = 1 - gx(s), whenever the series defining these generating functions converge.