A circle in the xyxyx, y-plane has the equation (x+18.5)^2+(y-3.1)^2=71(x+18.5) 2 +(y−3.1) 2 =71left parenthesis, x, plus, 18, point, 5, right parenthesis, squared, plus, left parenthesis, y, minus, 3, point, 1, right parenthesis, squared, equals, 71. What is the center of the circle?