15. (8 points) Answer true or false to the following statements. Assume all mentioned func- tions are asymptotically positive. a. (2 points) If fi(2) = (g(x)) and f2(x) = (g(x)), then fi(2) + f2(2) = (g(x)). a. b. (2 points) If fi(x) = O(91(x) and f2(x) = (g(x)), then f(2) f2(0) = 12(91(x)92(x)). b. c. (2 points) If f() = O(g(x)) and g(x) = O(f(x)), then f(x) = O(g(x)). C. d. (2 points) If f(x) = (g(2)), then af (0) = 2(g(x)). d