document.write( "Question 321940: please solve this problem:\r
\n" ); document.write( "\n" ); document.write( "For what value of k will the equation below describe a circle of radius 3 units?
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\n" ); document.write( "\n" ); document.write( "x^2 + Y^2 + 2X - 4Y + K = 0 \n" ); document.write( "

Algebra.Com's Answer #230507 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
Complete the square in x and y.
\n" ); document.write( " $\"x%5E2+%2B+y%5E2+%2B+2x+-4y+%2B+K+=+0\"$
\n" ); document.write( " $\"x%5E2%2B+2x++%2B+y%5E2-4y+%2B+K+=+0\"$
\n" ); document.write( " $\"%28x%5E2%2B+2x%2B1%29++%2B+%28y%5E2-4y%2B4%29+%2B+K+=+1%2B4\"$
\n" ); document.write( " $\"%28x%2B1%29%5E2%2B%28y-2%29%5E2=5-K\"$
\n" ); document.write( "Compare to the general equation of a circle centered at ( $\"h\"$ , $\"k\"$ ) with a radius $\"R\"$ .
\n" ); document.write( " $\"%28x-h%29%5E2%2B%28y-k%29%5E2=R%5E2\"$
\n" ); document.write( " $\"R%5E2=5-K=9\"$
\n" ); document.write( " $\"highlight%28K=-4%29\"$ \n" ); document.write( "

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