d.
the equation for a circle is
[tex](x-h)^2 + (y-k)^2=r^2[/tex]
with the point (h,k) being the center of the circle, and radius r.
your circle is centered at (1,4) and a radius of 8. plugging those in you get the equation
[tex](x-1)^2+(y-4)^2=8^2 \\ (x^2-2x+1)+(y^2-8x+16) = 64 \\ x^2+y^2-2x-8y+17=64 \\ x^2+y^2-2x-8y-47=0[/tex]
