Ihave the graph picture how do i post it ? .according to the graph below, how many years from now will the cost of a new computer be closest to the cost of tuition, but still higher?

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.