Answer:
See below
Step-by-step explanation:
arrange to standard form (x-h)^2 + (y-k)^2 = r^2 h,k = center r = radius
x^2 - 4x + y^2 + 2y = 4 complete the square for 'x' and 'y'
(x-2)^2 - 4 + (y-1)^2 -1 = 4
(x-2)^2 + ( y-1)^2 = 4 + 4 + 1 = 9 '9' is equal to r^2 so r = 3
center = 2,1 radius = 3
