Half of a pizza with broccoli and half with mushroom george 8 one-third of the broccoli part and one fourth of the mushroom part how much of pizza did he eat

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.