document.write( "Question 381601: Which of the following solutions to the quadratic inequality\r
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document.write( "(x - 2)(x + 1) > 4\r
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document.write( "is correct? Explain why the others are incorrect.\r
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document.write( "a) Solution 1
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document.write( "Since (x - 2)(x + 1) > 4 means that x - 2 > 4 or x + 1 > 4 ,we have the following:\r
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document.write( "if x - 2 > 4 , then x > 6 and if x + 1 > 4 , then x > 3.
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document.write( "Therefore the solution to the inequality is the interval (3,∞).\r
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document.write( "b) Solution 2
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document.write( "Since (x - 2)(x + 1) > 4 means that (x - 2)(x + 1) - 4 > 0 , we have the following:\r
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document.write( "Either (x - 2)(x + 1) > 0 or -4 > 0 and since -4 is never greater than 0 we
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document.write( "need only worry about (x - 2)(x + 1) > 0 .\r
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document.write( "Now, since (x - 2)(x + 1) > 0 implies that either x - 2 > 0 or x + 1 > 0 , the
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document.write( "solution to the inequality must be the interval (-1,∞).\r
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document.write( "c) Solution 3
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document.write( "Since (x - 2)(x + 1) > 4 means that (x - 2)(x + 1) - 4 > 0 , and (x - 2)(x + 1) - 4 > 0 is equivalent to writing x^2 - x - 6 > 0 and x^2 - x - 6 = 0 when x = -2 and x = 3 ,the solution to the inequality must be the interval (-2,3).\r
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document.write( "d) Solution 4
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document.write( "Since (x - 2)(x + 1) > 4 means that (x - 2)(x + 1) - 4 > 0 , and (x - 2)(x + 1) - 4 > 0 is equivalent to writing x^2 - x - 6 > 0 and x^2 - x - 6 = 0 when x = -2 and x = 3 , the solution to the inequality must be the interval (-∞,-2)and(3,∞) \n" );
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Algebra.Com's Answer #270678 by rapaljer(4671)![]() ![]() You can put this solution on YOUR website! Answer D is correct, although it is difficult to understand. \r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( "Dr Rapalje\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |