Boundedness

If a function’s range has some limits, the function is bounded. If the function’s range has no limits, the function is unbounded. Are these functions bounded or unbounded? If bounded, do they have an upper bound, lower bound, or both?

1. f(x) = 3x -9

2. f(x) = -x^{2}

3. f(x) = |x – 2|

4. f(x) = x^{3}

5. f(x) = 1/(x^{2} + 1)