Help Understanding Math Concepts [URGENT]

There are some problems I dont know how to work out that I need to understand for tommorows test. If you could just solve them for me with abit of explaining, that would be awesome.

1. x^(1/2) - 3x^(1/3) = 3x^(1/6) - 9

2. 4(x+1)^(1/2) - 5(x+1)^(3/2) + (x+1)^(5/2) = 0

3. If a = [(b^2)/(c^3)] * k, how is values of a changed when values of b + c are halved.

4. If 3x - x^2 > 2 and y^2 + y < 2, find restriction on product xy.

THANK YOU SO MUCH FOR ANSWERING (If you did). Ill continue to try to solve these on my own, but I have been going for hours on them already.