Finding the equation of the standard form:
[tex]\begin{gathered} x^2+y^2+8x-10y-23=0 \\ x^2+y^2+8x-10y=23 \\ x^2+8x+16+y^2-10y+25=23+16+25 \\ \\ \\ (x+4)^2+(y-5)^2=64 \end{gathered}[/tex]
Based on the image, h = -4, k = 5 and r = 8, then...
Answer:
Center: ( -4, 5)
Radius: 8