Question 322575
Complete the square in x and y,
{{{x^2 + y^2 + 2x + 4y-9=0}}}
{{{(x^2+2x+1)+(y^2+4y+4)-9=1+4}}}
{{{(x+1)^2+(y+2)^2=14}}}
Compare to the general equation of a circle centered at (h,k) with radius R,
{{{(x-h)^2+(y-k)^2=R^2}}}
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(h,k)=(-1,-2)