Write the equation of a circle with a center at (-7,4) and a diameter of 18.

Answer:
(x+7)^2 + (y - 4)^2 = 81. This matches
Answer Choice D.
Step-by-step explanation
Apply the standard equation of a circle with
center at (h, k) and radius r:
(x - h)^2 + (y - k)^2 = r^2
Here (h, k) is (-7, 4) and r is 18/2 or 9, and so the desired equation is
(x+7)^2 + (y - 4)^2 = 81. This matches Answer Choice D.