Answer:
x^2+y^2+2x-4y-1=0
(x^2+2x)+(y^2-4y)=1
x^2+2x+1+y^2-4y+4=1+1+4
(x+1)^2 + (y^2-2)^2=6
c=(-1,2) r=squareroot of 6
