Question 79149
x and y both squared with the same coefficient on the square terms means a circle


the rest of the terms give the location of the center and the radius ... the general equation is {{{(x-h)^2+(y-k)^2=r^2}}}


complete the squares for x and y by taking 1/2 of the coefficient of the first order term, square it and add it


{{{x^2+8x+(8/2)^2+y^2-4y+(-4/2)^2=-11+(8/2)^2+(-4/2)^2}}} ... so {{{(x+4)^2+(y-2)^2=9}}}


this is a circle centered at (-4,2) with a radius of 3