Answer:
(x+2)^2 + (y-4)^2 = 65
Step-by-step explanation:
r^2 = (4-(-4))^2 + (-1-(-2))^2 = 65
center = (-2, 4) so you add 2 to x and subtract 4 from y
If one of our zeros is 4, then the factor is x-4. If the second zero is 5i, then the conjugate root theorem says there HAS to be a root that is -5i. So our 3 factors are (x-4)(x+5i)(x-5i). We will FOIL out these factors to get the polynomial. Let's start with the ones that contain the imaginary numbers. Doing that mutliplication we get x^2-25i^2. i^2 is equal to -1, so what that expression simplifies down to is

. Now we will multiply in that last factor of (x-4):

. FOILing out we have

. There you go!