Question 1146113
x^2+y^2+10y=-9


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{{{x^2+y^2+10y=-9}}}

{{{x^2+y^2+10y+5^2 =-9+5^2}}}

{{{x^2+(y+5)^2=16}}}

{{{highlight(x^2+(y+5)^2=4^2)}}}