(1 -1) ##2sqrt5 20pi62.83##
The of a circle is
##color(red)(|bar(ul(color(white)(a/a)color(black)((x-a)^2+(y-b)^2=r^2)color(white)(a/a)|)))##
where (a b) are the coords of centre and r the radius
now ##(x-1)^2+(y+1)^2=20 is in this form##
and by comparison: a = 1 b = -1 and ##r^2=20 ##
centre = (a b) = (1 -1) r##=sqrt20=2sqrt5##
and area##=pir^2=pixx(sqrt20)^2=20pi 62.83##