document.write( "Question 92797: Find the domain and range for the function. Use interval notation.\r
\n" ); document.write( "\n" ); document.write( "f(x)= (x^2 + x - 12)/[(x-3)(x+5)]
\n" ); document.write( "

Algebra.Com's Answer #67530 by mathispowerful(115)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "\"f%28x%29=+%28x%5E2+%2B+x+-+12%29%2F%28%28x-3%29%28x%2B5%29%29\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "First simplify it:\r
\n" ); document.write( "\n" ); document.write( "factor the numerator. we get\r
\n" ); document.write( "\n" ); document.write( "\"%28x%2B4%29%28x-3%29%2F%28%28x-3%29%28x%2B5%29%29\",\r
\n" ); document.write( "\n" ); document.write( "cancel the common factor x-3\r
\n" ); document.write( "\n" ); document.write( "we get \"%28x%2B4%29%2F%28x%2B5%29\"\r
\n" ); document.write( "\n" ); document.write( "for a rational expression, the denominator can not be 0,\r
\n" ); document.write( "\n" ); document.write( "so x can not equal to -5\r
\n" ); document.write( "\n" ); document.write( "the domain is any real number except -5.\r
\n" ); document.write( "\n" ); document.write( "The range: Let's simplify \"%28x%2B4%29%2F%28x%2B5%29\" further\r
\n" ); document.write( "\n" ); document.write( "\"%28x%2B4%29%2F%28x%2B5%29\" = \"%28x%2B5-1%29%2F%28x%2B5%29\"
\n" ); document.write( "=\"1-1%2F%28x%2B5%29\"\r
\n" ); document.write( "\n" ); document.write( "let's take a look at the fraction \"1%2F%28x%2B5%29\"\r
\n" ); document.write( "\n" ); document.write( "when x is in the neighborhood of -5, the fraction can be positive infinity and
\n" ); document.write( "negative infinity, and thus \"1-1%2F%28x%2B5%29\" can be both positive infinity and
\n" ); document.write( "negative infinity.\r
\n" ); document.write( "\n" ); document.write( "so the range is from negative infinity to positive infinity.\r
\n" ); document.write( "\n" ); document.write( "this conclusion can be verified by the graph of \"f%28x%29=+%28x%5E2+%2B+x+-+12%29%2F%28%28x-3%29%28x%2B5%29%29\" below:\r
\n" ); document.write( "\n" ); document.write( "\"graph%28200%2C200%2C+-5.05%2C-4.95%2C+-1000%2C+1000%2C++%281-1%2F%28x%2B5%29%29%29\"
\n" ); document.write( "
\n" );