document.write( "Question 149248: (x-8/x+5)/(x-9/x+4) why cant -5, 9, and -4 not allowable replacements for the variable x. \r
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Algebra.Com's Answer #109499 by nerdybill(7384)\"\" \"About 
You can put this solution on YOUR website!
If a denominator is zero, the term is \"undefined\".
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\n" ); document.write( "(x-8/x+5)/(x-9/x+4)
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\n" ); document.write( "if x=-5, we would have:
\n" ); document.write( "(x-8/x+5)/(x-9/x+4)
\n" ); document.write( "(x-8/0+5)/(x-9/x+4)
\n" ); document.write( "(x-8/0)/(x-9/x+4)
\n" ); document.write( "Notice the numerator (x-8)/0 -- this is undefined
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\n" ); document.write( "if x=9, we would have:
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\n" ); document.write( "(x-8/x+5)/(0-9/x+4)
\n" ); document.write( "(x-8/x+5)/(0/x+4)
\n" ); document.write( "(x-8/x+5)/(0)
\n" ); document.write( "Again we have a denominator equal to zero -- undefined
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\n" ); document.write( "if x = -4, we would have:
\n" ); document.write( "(x-8/x+5)/(x-9/x+4)
\n" ); document.write( "(x-8/x+5)/(x-9/-4+4)
\n" ); document.write( "(x-8/x+5)/(x-9/0)
\n" ); document.write( "Notice the denominator (x-9)/0 -- this is undefined
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