We must complete the square for both x and y, so we divide the coefficient of the x and y terms by 2, square them, and add them to both sides
And now we can factor
Can you sketch that now or do you need further assistance?
(x - 8)^2 + (y + 4)^2 = 64 = 8^2
compare it with the standard equation of a circle, that is
(x - h)^2 + (y + 4)^2 = r^2,
h,k is the CORDINATE of the center of the CIRCLE, where r is the radius.
from (x - 8)^2 + (y + 4)^2 = 64 = 8^2; center coordinate is (h,k) is (8,-4) and r = 8.
see the graph . . . .
if the standard equation of the circle awe you, resort to point plotting, maybe you have not encounter yet ANALYTIC GEOMETRY.