document.write( "Question 61071: find the center and the radius of the circle:
\n" ); document.write( "x2 + y2 - 12x-16y-21 =0 \n" ); document.write( "

Algebra.Com's Answer #41989 by joyofmath(189) $\"\"$ $\"About$

You can put this solution on YOUR website!
find the center and the radius of the circle:
\n" ); document.write( " $\"x%5E2+%2B+y%5E2+-+12x-16y-21+=+0\"$ \r
\n" ); document.write( "\n" ); document.write( "Add 36 to both sides: $\"x%5E2-12x%2B36+%2B+y%5E2+-+12x-16y-21+=+36\"$
\n" ); document.write( "Rewrite x-expression: $\"%28x-6%29%5E2+%2B+y%5E2-16y-21+=+36\"$
\n" ); document.write( "Add 64 to both sides: $\"%28x-6%29%5E2+%2B+y%5E2-16y%2B64+-21+=+36%2B64=100\"$
\n" ); document.write( "Rewrite y-expression: $\"%28x-6%29%5E2+%2B+%28y-8%29%5E2+-+21+=+100\"$
\n" ); document.write( "Add 21 to both sides: $\"%28x-6%29%5E2+%2B+%28y-8%29%5E2+=+121\"$ \r
\n" ); document.write( "\n" ); document.write( "The center of the circle is (6,8).
\n" ); document.write( "The radius = $\"sqrt%28121%29+=+11\"$ . \n" ); document.write( "

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