Thread: Proof of Infinite Limit

I missed the classes where we learned these and I'm trying to do some practice, but I can't find any examples with solutions, can anyone please explain how to do either of the following:
1. prove by definition that lim as n tends to infinity(-n^2 + 10n + 100)=-infinity
2.let {xn}n tends to infinity and {yn}n tends to infinity be two convergent (in R) sequences such that xn>or=yn for all natural numbers n. Show that:

as both tend to infinity lim xn>or=lim yn