What is the center of the circle represented by this equation? (x – 7)2 + (y + 4)2 = 9?

The general form of a circle at center (h,k) and with radius r is:
(x - h)² + (y - k)² = r²

In your case, you can match your equation to:
(x - 7)² + (y - (-4))² = 3²

So you have a circle centered at (7, -4) with a radius of 3.