Question 1197082
#3:


9x2+9y²+54x - 36y + 36 = 0


{{{9x^2+9y^2+54x-36y+36=0}}}

{{{x^2+y^2+6x-4y+4=0}}}

{{{x^2+6x+y^2-4y+4=0}}}

9 completes the square for x.
4 completes the square for y.  (already present in the equation)

{{{(x^2+6x+9)+(y^2-4y+4)=0+9}}}

{{{(x+3)^2+(y-2)^2=9}}}

{{{(x+3)^2+(y-2)^2=3^2}}}-----------the rest of the meaning and what to do should be already clear from here.