document.write( "Question 1158137: the circle with equation 2(x+4)^2+2(y-1)^2-18=0 has centre C and radius r units, where..?
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Algebra.Com's Answer #781053 by Edwin McCravy(20054)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "\"%28x-h%29%5E2%2B%28y-k%29%5E2=r%5E2\"\r\n" );
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document.write( "is the equation of a circle with center (h,k) and radius r units.  \r\n" );
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document.write( "Your equation is \r\n" );
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document.write( "\"2%28x%2B4%29%5E2%2B2%28y-1%29%5E2-18=0\"\r\n" );
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document.write( "Make it look like this:\r\n" );
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document.write( "      \"%28x-h%29%5E2%2B%28y-k%29%5E2=r%5E2\"\r\n" );
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document.write( "Divide every term by 2\r\n" );
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document.write( "\"2%28x%2B4%29%5E2%2F2%2B2%28y-1%29%5E2%2F2-18%2F2=0%2F2\"\r\n" );
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document.write( "\"%28x%2B4%29%5E2%2B%28y-1%29%5E2-9=0\"\r\n" );
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document.write( "Add +9 to both sides:\r\n" );
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document.write( "\"%28x%2B4%29%5E2%2B%28y-1%29%5E2=9\"\r\n" );
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document.write( "Now it looks like \r\n" );
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document.write( "\"%28x-h%29%5E2%2B%28y-k%29%5E2=r%5E2\"\r\n" );
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document.write( "-h = +4;   -k = -1\r\n" );
document.write( " h = -4;    k =  1\r\n" );
document.write( " r² = 9\r\n" );
document.write( "  r = 3\r\n" );
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document.write( "Therefore the center is (-4,1) and the radius in 3, and the\r\n" );
document.write( "graph looks like this:\r\n" );
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document.write( "Edwin
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