Question 1028352
Complete the Squares and put into standard form; and read the center (h,k) and radius r directly from the equation.


{{{x^2-2x+y^2+2y=18}}}
{{{x^2-2x+1+y^2+2y+1=18+1+1}}}-----*
{{{(x-1)^2+(y+1)^2=20}}}


Radius size is {{{2*sqrt(5)}}} and center of the circle is (1,-1).




*  Why this step was done is shown here:  <a href="https://www.algebra.com/my/Completing-the-Square-to-Solve-General-Quadratic-Equation.lesson?content_action=show_dev">A lesson which includes how to Complete The Square</a>