I am having some trouble with these questions

1) Let f(x)=2x²20x1

a. Find the values of x for which the slope of the curve y=f(x) is 0.

b. Find the values of x for which the slope of the curve y=f(x) is 4.

2) Findh(x) andg(x) such that f(x)=(hg)(x)

f(x)= 4x+2- (this has a square root symbol over it, I am just not sure how to put it on)

Suppose that g(x)=4x+2.

3) Find d²y/dx² for the following functions

a) y=3x sin (x²)

b) y= e^{-5x^2}