document.write( "Question 1119145: The equation of a circle in the xy plane is x^2+y^2+8x-10y=-5. What is the radius of the circle?
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Algebra.Com's Answer #734620 by ikleyn(53308) $\"\"$ $\"About$

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document.write( "Perform completing the squares for x and y separately to transform the given equation to the standard equation of the circle:\r\n" );
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document.write( "x^2 + y^2 + 8x - 10y = -5\r\n" );
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document.write( "(x^2 + 8x) + (y^2 - 10y) = -5                        <<<---=== first step - grouping\r\n" );
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document.write( "(x^2 + 8x + 16) + (y^2 - 10y + 25) = -5 + 16 + 25    <<<---=== identical transformations\r\n" );
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document.write( " +  = 36.                                 <<<---=== complete the squares\r\n" );
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document.write( "You got the standard equation of the circle.\r\n" );
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document.write( "Answer.  The radius of the circle is   = 6.\r\n" );
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