The general equation of a circle is given by
where (h,k) is the center of the circle and r is the radius
x² + y² -2x - 8y = 8
x² - 2x + y² - 8y = 8
(x² - 2x + ) + (y² -8y + ) = 8
Add square of half of the coefficient of x in the first paenthesis and the half of the square of the coefficient of y in the second parenthesis
Then add the two squaes at the right-hand side of the equation
(x² -2x +1 ) + (y² -8y + 16 ) = 8 + 1+ 16
(x-1)² + (y-4)² = 25
comparing this with the general equation
Center is ( 1, 4)
Radius is 5