Question 973674
x^2+y^2+2x-4y-31=0
x^2+2x +   ;;;    +y^2 +4y+ ;;   =31

x^2 +2x+1  + Y^2 -4y +4 = 31+5
(x+1)^2  + (y-2)^2=36

This is a circle with radius 6 and center (-1,2)