document.write( "Question 139830: What is the radius of the circle 2x^2+2y^2-8x+16y-32=0? I think it is 6??????? \n" ); document.write( "
Algebra.Com's Answer #101924 by jim_thompson5910(35256)\"\" \"About 
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\"2x%5E2%2B2y%5E2-8x%2B16y-32=0\" Start with the given equation\r
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\n" ); document.write( "\n" ); document.write( "\"2x%5E2-8x%2B2y%5E2%2B16y-32=0\" Rearrange the terms\r
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\n" ); document.write( "\n" ); document.write( "\"2x%5E2-8x%2B2y%5E2%2B16y=%2B32\" Add \"32\" to both sides\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x-2%29%5E2-8%2B2y%5E2%2B16y=%2B32\" Complete the square for the x terms\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x-2%29%5E2-8%2B2%28y%2B4%29%5E2-32=%2B32\" Complete the square for the y terms\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x-2%29%5E2%2B2%28y%2B4%29%5E2-40=%2B32\" Combine like terms\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x-2%29%5E2%2B2%28y%2B4%29%5E2=%2B32%2B40\" Add \"40\" to both sides\r
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\n" ); document.write( "\n" ); document.write( "\"2%28x-2%29%5E2%2B2%28y%2B4%29%5E2=72\" Combine like terms\r
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\n" ); document.write( "\n" ); document.write( "\"2%28%28x-2%29%5E2%2B%28y%2B4%29%5E2%29=72\" Factor out the common term 2\r
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\n" ); document.write( "\n" ); document.write( "\"%28x-2%29%5E2%2B%28y%2B4%29%5E2=36\" Divide both sides by 2\r
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\n" ); document.write( "\n" ); document.write( "Notice how the equation is now in the form \"%28x-h%29%5E2%2B%28y-k%29%5E2=r%5E2\". This means that this conic section is a circle where (h,k) is the center and \"r\" is the radius.\r
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\n" ); document.write( "\n" ); document.write( "Center: (2,-4)\r
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\n" ); document.write( "\n" ); document.write( "Radius: \"r=sqrt%2836%29=6\"\r
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\n" ); document.write( "\n" ); document.write( "Answer: \r
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\n" ); document.write( "\n" ); document.write( "So the radius of the circle is 6 units\r
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