document.write( "Question 261699: The equation x^2 + Bx + C = 0 has 5 as the sum of its roots and 15 as the sum of the squares of the roots. What is the value of C? \n" ); document.write( "
Algebra.Com's Answer #192836 by Edwin McCravy(20055)\"\" \"About 
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The equation x^2 + Bx + C = 0 has 5 as the sum of its roots and 15 as the sum of the squares of the roots. What is the value of C?
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document.write( "Let the roots be r and s.\r\n" );
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document.write( "Then B = -(r+s) and C = rs\r\n" );
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document.write( "Since the sum of the roots is 5,\r\n" );
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document.write( "B = -(r+s) = -(5) = -5\r\n" );
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document.write( "So\r\n" );
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document.write( "r+s = 5\r\n" );
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document.write( "Squaring both sides:\r\n" );
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document.write( "\"%28r%2Bs%29%5E2=5%5E2\"\r\n" );
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document.write( "\"r%5E2%2B2rs%2Bs%5E2=25\"\r\n" );
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document.write( "\"%28r%5E2%2Bs%5E2%29%2B2rs=25\"\r\n" );
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document.write( "The sum of the squarse of the roots is 15 so\r\n" );
document.write( "we replace \"r%5E2%2Bs%5E2\" by 15\r\n" );
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document.write( "\"15%2B2rs=25\"\r\n" );
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document.write( "\"2rs=10\"\r\n" );
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document.write( "\"rs=5\"\r\n" );
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document.write( "and since C = rs\r\n" );
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document.write( "C = 5\r\n" );
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document.write( "Edwin

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