document.write( "Question 31141This question is from textbook Intro Algebra
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Find the real number for which this rational expression is undefined:\r\n" );
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document.write( "   5x+9\r\n" );
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document.write( " 4x²-4x-15
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Algebra.Com's Answer #17849 by AnlytcPhil(1806)\"\" \"About 
You can put this solution on YOUR website!
Find the real number for which each rational expression is \r\n" );
document.write( "undefined.\r\n" );
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document.write( "    5x+9\r\n" );
document.write( " -----------\r\n" );
document.write( "  4x²-4x-15\r\n" );
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document.write( "A rational expression is undefined if its denominator is 0.\r\n" );
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document.write( "So set the denominator = 0 and solve for x.\r\n" );
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document.write( " denominator = 4x² - 4x - 15 = 0\r\n" );
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document.write( "The left side factors as\r\n" );
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document.write( "            (2x + 3)(2x - 5) = 0\r\n" );
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document.write( "Use to zero-factor principle.  Set each factor = 0 and solve:\r\n" );
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document.write( "Setting 2x + 3 = 0 gives x = -3/2\r\n" );
document.write( "Setting 2x - 5 = 0 gives x = 5/2\r\n" );
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document.write( "Therefore the expression is undefined for x = -3/2 or 5/2\r\n" );
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document.write( "Edwin\r\n" );
document.write( "AnlytcPhil@aol.com

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