document.write( "Question 171486: What are the steps to determine the restricted values?
\n" ); document.write( "x^2-4x-21/x^2+16 \n" ); document.write( "

Algebra.Com's Answer #126636 by Mathtut(3670) $\"\"$ $\"About$

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the denominator cannot be equal to zero or the results will be undefined.....so set the denominator equal to zero and solve
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\n" ); document.write( " $\"x%5E2%2B16=0\"$
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\n" ); document.write( " $\"x%5E2=-16\"$ \r
\n" ); document.write( "\n" ); document.write( "so the only restricted values are complex numbers.....all real numbers solutions will work in this equation.\r
\n" ); document.write( "\n" ); document.write( "to be specific x= $\"sqrt%28-16%29\"$ = $\"sqrt%28-1%2816%29%29\"$ = $\"4i\"$ \n" ); document.write( "

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