is the equation of a circle with center at and radius
Move the constant to the RHS
Divide the coefficient on the first degree term by 2 and square the result. Add that result to both sides, completing the square in . Do the same thing with the coefficient on the first degree term.
Collect terms in the RHS and factor the two perfect square trinomials in the LHS.
Finally, rewrite your equation thus:
Now you can determine the center and radius by inspection. Compare to the pattern given at the beginning.
John
My calculator said it, I believe it, that settles it
