document.write( "Question 287379: Find the Center and radius of the circle whose equation is:\r
\n" ); document.write( "\n" ); document.write( "x^2+8x+y^2+1y-2=0\r
\n" ); document.write( "\n" ); document.write( "I can't seem to get the correct radius although I can get the center. Your help would be most appreciated. \n" ); document.write( "

Algebra.Com's Answer #208279 by Fombitz(32388) $\"\"$ $\"About$

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Complete the square in x and y.
\n" ); document.write( " $\"x%5E2%2B8x%2By%5E2%2B1y-2=0\"$
\n" ); document.write( " $\"%28x%5E2%2B8x%29%2B%28y%5E2%2By%29=2\"$
\n" ); document.write( " $\"%28x%5E2%2B8x%2B16%29%2B%28y%5E2%2By%2B1%2F4%29=2%2B16%2B1%2F4%0D%0A\"$
\n" ); document.write( " $\"%28x%2B4%29%5E2%2B%28y%2B1%2F2%29%5E2=8%2F4%2B64%2F4%2B1%2F4=73%2F4\"$
\n" ); document.write( " $\"%28x%2B4%29%5E2%2B%28y%2B1%2F2%29%5E2=73%2F4\"$
\n" ); document.write( "Compare to the general equation for 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( " $\"h=-4\"$
\n" ); document.write( " $\"k=-1%2F2\"$
\n" ); document.write( " $\"R=sqrt%2873%29%2F2\"$ \n" ); document.write( "

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