The equation represents a circle.
If you factorise the equation, you get:
[tex]x^2 + y^2 + 2x +1 =0 \\(x+1)^2-1+(y)^2=0\\(x+1)^2+y^2=1[/tex]
This final equation shows the equation of a circle, as a circle's equation is given as:
[tex](x+a)^2+(y+b)^2=r^2[/tex]