Please gave me the solution within 25/30 mins. TIA

24. Let f:R R and let f(x) > 0 for all x R. Show that f(x) is strictly increasing if and only if the func- tion g(x) = 1/f(x) is strictly decreasing. 25. Let f: R R and let f(x) > 0 for all x R. Show that f(x) is strictly decreasing if and only if the func- tion g(x) = 1/f(x) is strictly increasing. 26. a) Prove that a strictly increasing function from R to it- self is one-to-one. b) Give an example of an increasing function from R to itself that is not one-to-one