(x+4)^2 / 9 - (y+3)^2 / 16 = 1
a^2 = 16 and b^2 = 9
a = +4 and -4
b = +3 and -3
Center is (-4, -3)
Vertices is (-4 + a, -3) and (-4 - a, -3)
Vertices is (-1, -3) and (-7, -3)
You just need to plug the values: you have to multiply
and
, and then divide the result by -3.
So, if
, we have 
Which means that 
And the final answer is 
Find the critical points of
:


All three points lie within
, and
takes on values of

Now check for extrema on the boundary of
. Convert to polar coordinates:

Find the critical points of
:



where
is any integer. There are some redundant critical points, so we'll just consider
, which gives

which gives values of

So altogether,
has an absolute maximum of 65/16 at the points (0, -1/2) and (0, 1/2), and an absolute minimum of 3 at (-1, 0).