Question 156547
{{{x^2+y^2+8x-12y+43=0}}}
then
{{{x^2+8x+y^2-12y+43=0}}}
then (completing squares)
{{{(x^2+8x+16)+(y^2-12y+36)-16-36+43=0}}}
{{{(x+4)^2+(y-6)^2-9=0}}}
{{{(x+4)^2+(y-6)^2=9}}}

then center is (-4,6) and radius is 3

You can do the exercises using formulas too