You can put this solution on YOUR website! The general form for a hyperbola is: (horizontally-oriented)
or (vertically-oriented)
The center of the hyperbola, in both cases, is the point (h, k)
Except for the +'s in your numerators, your equation is already in this form. All you have to do is rewrite the additions as equivalent subtractions:
This makes the center: (-3, -9)