document.write( "Question 932792: Given the equation x^2 - 12x + y^2 - 16y + 84=0, complete the square for both x and y. What is the result? How do I do this? \n" ); document.write( "
Algebra.Com's Answer #566403 by MathLover1(20849)\"\" \"About 
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\"x%5E2+-+12x+%2B+y%5E2+-+16y+%2B+84=0\"\r
\n" ); document.write( "\n" ); document.write( "\"%28x%5E2+-+12x%2B__%29+%2B+%28y%5E2+-+16y+%2B__%29%2B+84=0\"\r
\n" ); document.write( "\n" ); document.write( "since we need \"b%5E2\" to have \"a%5E2%2B2ab%2Bb%5E2\" and we are given \"%28x%5E2+-+12x%2B_b%5E2_%29\" , where \"a=1\", \"2ab=12\",then =>\"2%2A1%2Ab=12\"=>\"b=6\" and \"b%5E2=36\"\r
\n" ); document.write( "\n" ); document.write( "and \"%28y%5E2+-+16y+%2B_b%5E2_%29\", \"a=1\", \"2ab=-16\",then =>\"2%2A1%2Ab=-16\"=>\"b=-8\" and \"b%5E2=64\"\r
\n" ); document.write( "\n" ); document.write( "so, to complete the square, first write \"84\" as \"36%2B64-16\"}, add \"36\" to \"%28x%5E2+-+12x%2B_b%5E2_%29+-b%5E2\" and subtract it so the equation doesn't change\r
\n" ); document.write( "\n" ); document.write( "\"%28x%5E2+-+12x%2B36%29+-36%2B+%28y%5E2+-+16y+%2B64%29-64%2B+84=0\"\r
\n" ); document.write( "\n" ); document.write( "\"%28x%5E2+-+6%29%5E2+%2B+%28y%5E2+-8%29%5E2-36-64%2B+84=0\"\r
\n" ); document.write( "\n" ); document.write( "\"%28x%5E2+-+6%29%5E2+%2B+%28y%5E2+-8%29%5E2-100%2B+84=0\"\r
\n" ); document.write( "\n" ); document.write( "\"%28x%5E2-6%29%5E2%2B%28y%5E2-8%29%5E2-16+=+0\"\r
\n" ); document.write( "\n" ); document.write( "\"%28x%5E2-6%29%5E2%2B%28y%5E2-8%29%5E2=16+\"\r
\n" ); document.write( "\n" ); document.write( "so, you have a circle with center at (\"6\",\"-8\") and radius \"r=4\"\r
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