Intervals on Which a Function Is Increasing or Decreasing In Exercises 11-22, find the open intervals on which the function is increasing or decreasing. 11. g(x) = x2 - 2x - 8 12. h(x) = 12x - r 13. y = x16 - x2 14. y = x + X 15. f(x) = sin x - 1, 0