document.write( "Question 1002172: find all numbers for which the following rational expression is undefined. If the rational expression is defined for all real numbers, state so.
\n" ); document.write( "5/(z-4)(z+2) \n" ); document.write( "

Algebra.Com's Answer #619145 by MathLover1(20849) $\"\"$ $\"About$

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\n" ); document.write( "\n" ); document.write( " $\"5%2F%28z-4%29%28z%2B2%29\"$ \r
\n" ); document.write( "\n" ); document.write( "Rational expressions are undefined when the denominator is equal to $\"0\"$ . Since the denominator is equal to $\"%28z-4%29%28z%2B2%29\"$ , make it equal to $\"0\"$ and solve for $\"z\"$ .\r
\n" ); document.write( "\n" ); document.write( " $\"%28z-4%29%28z%2B2%29=0\"$ \r
\n" ); document.write( "\n" ); document.write( "if $\"%28z-4%29=0\"$ => $\"z=4\"$
\n" ); document.write( "if $\"%28z%2B2%29=0\"$ => $\"z=-2\"$ \r
\n" ); document.write( "\n" ); document.write( "the rational expression is defined for all real numbers excluding $\"z=4\"$ and $\"z=-2\"$ \n" ); document.write( "

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