1/2-1/7 in simplest form

Lola says these two expressions have the same value. expression a expression b which explains whether lola is correct?

Cole says the distance between points (-5,0) and (0,-5)is 5 units. is he correct? explain why or why not.

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.