document.write( "Question 534146: find the center and radius of the circle with equation x2-4x+y2-6y+9=0. \n" ); document.write( "

Algebra.Com's Answer #351377 by Earlsdon(6294) $\"\"$ $\"About$

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Find the center and radius:
\n" ); document.write( " $\"x%5E2-4x%2By%5E2-6y%2B9+=+0\"$ Complete the square in x by adding the square of half the x-coefficient $\"%28-4%2F2%29%5E2+=+4\"$ to both sides.
\n" ); document.write( " $\"%28x%5E2-4x%2B4%29%2B%28y%5E2-6y%2B9%29+=+4\"$ Now factor the x-terms and the y-terms.
\n" ); document.write( " $\"%28x-2%29%5E2%2B%28y-3%29%5E2+=+4\"$ Compare with the standard form for a circle with center at (h,k) and radius r:
\n" ); document.write( " $\"%28x-h%29%5E2%2B%28y-k%29%5E2+=+r%5E2\"$
\n" ); document.write( "You can see that the center is at (2,3) and the radius is 2.
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