Find the intervals in which the following functions are strictly increasing or decreasing:(a) `x^2+2x-5` (b) `10-6x-2x^2` (c) `-2x^3-9x^2-12 x+1` (d) `6-9x-x^2`(e) `(x+1)^3(x-3)^3`

Explanation

To find the intervals in which the given functions are strictly increasing or decreasing, we will follow these steps for each function:

1. **Find the first derivative of the function.**
2. **Set the first derivative greater than zero to find the intervals of increase.**
3. **Set the first derivative less than zero to find the intervals of decrease.**
4. **Determine the critical points and test the intervals.**

Let's solve each function step by step.
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