Find the absolute and local maximum and minimum values of $f(x)=3 - \sqrt {7 x}$. If there are multiple points in a single category list the points in increasing order in x value and enter N in any blank that you don't need to use.

Absolute maxima
x = y =
x = y =
x = y =

Absolute minima
x = y =
x = y =
x = y =

Local maxima
x = y =
x = y =
x = y =

Local minima
x = y =
x = y =
x = y =

You can earn partial credit on this problem.