My friend, you have too many questions, and you have to explain them in detail. I can only give you a hint here.

The solutions to several problems are the same, and the steps are as follows:

1. derivative

2. Let the derivative = 0 and find the zero point.

3. Discuss the positive and negative derivatives in the interval with zero domain, so as to determine the increase or decrease of the original function in this interval.

4. According to the conclusion in 3. , judge the increase or decrease interval or curve concave and convex or extreme value of function.

Attached below are pictures of 1 and 2 questions: