i cant seem to find the derivative of the following functions, and ive been trying to solve them for close to 4 hours. ive used quotient rule, product rule, chain rule but i still dont get the answers. here they are:

2x^3 - 1 all over x^2

root x(x^3 - x)

root(x-1)(x +1)

((root x) + 2)^-2/3

please help!!