Where "a" and "b" are the semi-axis lengths in the x- and y-directions, respectively, the general form of the equation for an ellipse centered at (h, k) can be written as
(x-h)²/a² + (y-k)²/b² = 1
Substituting your given values of a=4, b=6, h=-4, k=6, your equation is
(x+4)²/16 + (y-6)²/36 = 1