document.write( "Question 882022: If $\"y=f%28x%29+=+%283x+%2B+7%29%2F%284x+-+9%29+\"$ , show that $\"x+=+f%28y%29\"$ \n" ); document.write( "

Algebra.Com's Answer #532686 by Edwin McCravy(20056) $\"\"$ $\"About$

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$\"y=%22f%28x%29%22+=+%283x+%2B+7%29%2F%284x+-+9%29+\"$ , show that $\"x+=+%22f%28y%29%22\"$
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document.write( "Sorry but that is just not true in general.  \r\n" );
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document.write( "Here is a disproof by a counterexample.\r\n" );
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document.write( "If it were true in general it would be true if x = 1\r\n" );
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document.write( "Suppose x = 1\r\n" );
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document.write( "Now in order for what we are asked to prove to be true in this\r\n" );
document.write( "case, we must end up with\r\n" );
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document.write( ", which in this case would be\r\n" );
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document.write( "However f(-2) is found by substituting x=-2 in\r\n" );
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document.write( "which is false.  So what you were asked to\r\n" );
document.write( "prove is not true.\r\n" );
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document.write( "Edwin

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