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17-20. True-False Determine whether the statement is true or false. Explain your answer. 17. f limx-a f(x) and lime-ag(x) exist, then so does limx-alf(x) + g(x)]. 18. If lime-ag(x) =0 and limx-a f(x) exists, then limx-alf(x)/g(x)] does not exist. 19. [f limx-a f(x) and lime-a g(x) both exist and are equal, then lime-alf(x)/g(x)] =1. 20. If f(x) is a rational function and x = a is in the domain of f, then limx -a f(x) = f(a). 21-22. First rationalize the numerator and then find the limit. x2+4 - 2 21. lim x+4-2 22. lim X-+0