document.write( "Question 1050741: Anton is four years older than Lisa. The product of his
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Algebra.Com's Answer #666351 by Edwin McCravy(20056)\"\" \"About 
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Anton is four years older than Lisa. The product of his
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document.write( "Lisa's present age = L\r\n" );
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\n" ); document.write( "Anton is four years older than Lisa.
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document.write( "Anton's present age = L+4\r\n" );
document.write( "Anton's age 3 years from now = (L+4)+3 = L+4+3=L+7\r\n" );
document.write( "Lisa's age 2 years ago = L-2\r\n" );
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\n" ); document.write( "The product of his age 3 years from now and Lisa's age two years ago is 90 years
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document.write( "\"%28L%2B7%29%28L-2%29\"\"%22%22=%22%22\"\"90\"\r\n" );
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document.write( "Use FOIL on the left\r\n" );
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document.write( "\"L%5E2%2B5L-14\"\"%22%22=%22%22\"\"90\"\r\n" );
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document.write( "Get 0 on the right by subtracting 90 from both \r\n" );
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document.write( "\"L%5E2%2B5L-104\"\"%22%22=%22%22\"\"0\"\r\n" );
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document.write( "The factor pairs that have product 104 are\r\n" );
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document.write( "104×1, 52×2, 26×4, 13×8\r\n" );
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document.write( "Only 13 and 8 have difference 5.  So we factor\r\n" );
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document.write( "\"%28L%2B13%29%28L-8%29\"\"%22%22=%22%22\"\"0\"\r\n" );
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document.write( "L+13 = 0;     L-8 = 0\r\n" );
document.write( "   L = -13      L = 8\r\n" );
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document.write( "Ignore the negative answer.\r\n" );
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document.write( "Lisa's present age = L = 8\r\n" );
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document.write( "Anton's age = L+4 = 8+4 = 12\r\n" );
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document.write( "And indeed 15×6 = 90.\r\n" );
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document.write( "Edwin
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