In Problems 9-52, determine where the function is (a) increasing, (b) decreasing, and (c) determine where relative extrema occur. Do not sketch the graph.
16. y = 3 + 12x - x^2
38. y = 4x^2 - 25
18. y = x^3 - 6x^2 + 12x - 6
40. y = x^3 - 9x
30. y = x^2 - 2
42. y = x^2 + 34
44. y = 1 - x^(2/3)
46. y = x ln x
52. y = x + e^(-x)
48. y = x - e^x