document.write( "Question 360298: Solve the inequality x(x + 3) > 4. Give your solution in interval notation, using INF for infinity. \n" ); document.write( "

Algebra.Com's Answer #257109 by robertb(5830) $\"\"$ $\"About$

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$\"x%28x%2B3%29%3E4\"$ ,
\n" ); document.write( " $\"x%5E2%2B3x-4%3E0\"$ ,
\n" ); document.write( " $\"%28x-1%29%28x%2B4%29%3E0\"$ .\r
\n" ); document.write( "\n" ); document.write( "The critical values of the inequality are 1 and -4.
\n" ); document.write( "Choose any number less than -4: pick -5. Now $\"%28-5-1%29%2A%28-5%2B4%29%3E0\"$ . Therefore ( $\"-infinity\"$ , -5) is part of the solution set.
\n" ); document.write( "Choose any number between -4 and 1: pick 0. Now $\"%280-1%29%2A%280%2B4%29%3C0\"$ . Therefore (-4, 1) is not part of the solution set.
\n" ); document.write( "Choose any number greater than 1: pick 2. Now $\"%282-1%29%2A%282%2B4%29%3E0\"$ . Therefore (1, $\"infinity\"$ ) is part of the solution set.
\n" ); document.write( "The critical values themselves don't satisfy the original inequality. Therefore the solution set is ( $\"-infinity\"$ , -5)U(1, $\"infinity\"$ ).
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