The equation for a circle is x2-8x+y2-2y-8=0 .

What is the equation of the circle in standard form?

(x-16) 2 + (y-1) 2=25

(x-16) 2 + (y-1) 2=16

(x-4) 2 + (y-1) 2=25

(x-4) 2 + (y-1) 2=16

You can analyze it in this way:

1) (2) in y2-2y can show that was (y-1) ^2 so we add - 1 to - 8 = > - 9

2) (8) in x2-8x show us that was (x-4) ^2 so we add - 16 to - 9 = > - 25

and finally we have: (x-4) ^2 + (y-1) ^2 = 25

it means C is true!

Answer: (x-4) 2 + (y-1) 2=25 is the answer