Would anyone be able to help me solve a few calculus problems? I have about 7 I need help with.?

I figured out a few of them already, but I don't know where to start with:

Thank you very much in advance!

1.)Find all the relative extrema and classify each as a maximum or minimum

f(x)=7-2x^2

2.)Find all the relative extrema and classify each as a maximum or minimum

f(x)=-5x^2+6x-2

3.)Find all the relative extrema and classify each as a maximum or minimum

f(x)=-27^3+9x+2

4.)Differentiate implicity to find dy/dx. Then find the slope of the curve at the given point.

y^2-x^3=41; (2,-7)

dy/dx=

slope of the given point is=

5.)Differentiate implicity to find dy/dx. Then find the slope of the curve at the given point.

x^2y^2=16 (1,4)

dy/dx=

slope of the curve at (1,4) is=

Post one at a time and help may be available.

Not a good idea to send SEVEN at the one go.

What are the questions, and what do you have so far?