document.write( "Question 675192: The expression ( x + 1)(x + 2) > 0 is equivalent to which of the following?
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\n" ); document.write( " (e) x < -2 or x > -1
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Algebra.Com's Answer #419610 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "(x + 1)(x + 2) > 0\r\n" );
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document.write( "We find the critical values of that which are the solutions to\r\n" );
document.write( "the equation which is found by replacing the > by =:\r\n" );
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document.write( "                             (x + 1)(x + 2) = 0\r\n" );
document.write( "                             x + 1 = 0    x + 2 = 0\r\n" );
document.write( "                                 x = -1;      x = -2\r\n" );
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document.write( "We put those two critical nubers on a number line:\r\n" );
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document.write( "                ----------o--o-------------------\r\n" );
document.write( "                -5 -4 -3 -2 -1  0  1  2  3  4  5\r\n" );
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document.write( "We test a value for x less that -2, say x = -3\r\n" );
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document.write( " (x + 1)(x + 2) > 0\r\n" );
document.write( "(-3 + 1)(-3 + 2 > 0\r\n" );
document.write( "       (-2)(-1) > 0\r\n" );
document.write( "              2 > 0\r\n" );
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document.write( "That is true so we shade the number to the left of -2\r\n" );
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document.write( "                <=========o--o-------------------\r\n" );
document.write( "                -5 -4 -3 -2 -1  0  1  2  3  4  5\r\n" );
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document.write( "Test a value for x between -2 and -1, say x = -1.5\r\n" );
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document.write( "     (x + 1)(x + 2) > 0\r\n" );
document.write( "(-1.5 + 1)(-1.5 + 2 > 0\r\n" );
document.write( "        (-0.5)(0.5) > 0\r\n" );
document.write( "              -0.25 > 0\r\n" );
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document.write( "That is false so we do not shade the number line between -3 and -2.\r\n" );
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document.write( "We test a value for x greater that -1, say x = 0\r\n" );
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document.write( " (x + 1)(x + 2) > 0\r\n" );
document.write( "  (0 + 1)(0 + 2 > 0\r\n" );
document.write( "         (1)(2) > 0\r\n" );
document.write( "              2 > 0\r\n" );
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document.write( "That is true so we shade the number line to the right of -1\r\n" );
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document.write( "                <=========o--o==================>\r\n" );
document.write( "                -5 -4 -3 -2 -1  0  1  2  3  4  5\r\n" );
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document.write( "                x < -2 or x > -1   [choice (e)]\r\n" );
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document.write( "The interval notation is an abbreviation for that number line:\r\n" );
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document.write( "                (-∞, -2) U (-1, ∞)\r\n" );
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document.write( "Edwin
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